MongoDB C100DBA - MongoDB Associate Database Administrator(Based on MongoDB 6.0 and 7.0+)

db.currentOp() reports information about operations that are currently in progress and accepts a filter document to restrict the output. The ns field in current-operation information identifies the namespace, typically in database.collection form. The regular expression /^qa\./ therefore matches namespaces beginning with qa., which isolates operations targeting collections in the qa database. Option C correctly supplies that namespace expression as a filter argument to db.currentOp(). Options A and B use a nonexistent db.listOps interface. Option D incorrectly treats ns as though it were a property or method chained from db.currentOp; filtering belongs inside the argument document. On current MongoDB versions, administrators are encouraged to use the $currentOp aggregation stage for more powerful filtering and composition, but the legacy helper remains the interface being tested here. Once the problematic operation is identified, the DBA can inspect details such as operation type, namespace, duration, waiting state, and client information before deciding whether additional action such as optimization or termination is justified. Thus C is the correct command.

Study Guide reference/topic:Performance Monitoring and Tuning - active operations, namespaces, long-running operation diagnostics, and currentOp.

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The documented mongosh helper is db.revokeRolesFromUser(), and its second argument is an array of roles to revoke. MongoDB permits each role in that array to be expressed either as an explicit document { role: < roleName > , db: < database > } or, when the role belongs to the database in which the command is run, as a simple role-name string. Option C uses the explicit role-document form and is therefore valid for a role named specialRole defined in myDB. Option E uses the shorthand string form and is valid when specialRole is in the current database context. Option A reverses the required document structure and does not supply the mandatory role and db keys. Options B and D use a singular helper, db.revokeRoleFromUser(), which is not the documented MongoDB method. The plural method name reflects that multiple roles can be revoked in a single operation. Administrators should also remember that revoking a directly assigned role does not necessarily remove privileges inherited through other roles. Among the choices, C and E are the syntactically valid revocation forms.

Study Guide reference/topic:Security, Networking, and Encryption - RBAC, user administration, and revokeRolesFromUser().

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MongoDB Enterprise auditing supports three standard destination values for audit events: syslog, file, and console. With the syslog destination, audit records are sent to the operating system ' s syslog facility where supported. With the file destination, events are written to a configured audit log path, and administrators can control the output format according to the supported audit configuration. With the console destination, audit events are emitted to standard output, which can be useful in containerized or centrally collected logging environments. A raw TCP/IP port is not itself an auditLog.destination value. Organizations can certainly forward logs over the network using operating-system or observability tooling, but that transport is external to MongoDB ' s destination setting. A MongoDB database is likewise not one of the supported audit destinations; keeping audit evidence independent from the system being audited is also preferable for integrity and compliance. Auditing records security-relevant actions and can be filtered to meet regulatory or operational requirements. Therefore the three valid destinations among the choices are syslog, file, and console: A, B, and E.

Study Guide reference/topic:Security, Networking, and Encryption - auditing, auditLog.destination, compliance logging, and audit configuration.

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Sharding is MongoDB ' s horizontal-scaling mechanism: it partitions a collection ' s data across multiple shards so a deployment can scale storage capacity and distribute query or write workload beyond the limits of one server. That directly supports deployments with very large datasets and high-throughput operations, making C correct. MongoDB also supports zone sharding, which associates ranges of shard-key values with selected shards. Zones can be used to keep particular data near a geographical region, satisfy locality requirements, or map data ranges to hardware tiers, so A is also correct. Option B overstates what sharding itself provides; cross-region consistency behavior depends on replication topology, read/write concerns, latency, and application design rather than simply enabling sharding. Option D describes a deployment that already fits comfortably in memory and meets performance goals, so sharding may add unnecessary operational complexity. Option E primarily describes replication: replica sets maintain redundant copies, provide elections, and improve availability. Production shards are themselves normally replica sets, but redundancy is a replication function rather than the defining purpose of sharding. Therefore the two functions represented here are geographic zone distribution and horizontal scale: A and C.

Study Guide reference/topic:Sharding Strategies and Scalable Deployments - horizontal scaling, large datasets, throughput, shard keys, and zone sharding.