What can a database specialist use to identify blocked queries on a DocumentDB cluster?

Answer options:

A.CloudWatch Logs
B.AWS X-Ray
C.CloudTrail Events
D.MongoDB currentOp command

Answer: D
Option A is incorrect because CloudWatch Logs does not contain details of queries that are currently executing on a DocumentDB cluster.
Option B is incorrect because AWS X-Ray is used for debugging and tracing requests in microservices applications.
Option C is incorrect because CloudTrail is a log of AWS services API activity. It cannot be used for monitoring and analyzing the performance of DocumentDB databases.
Option D is CORRECT because MongoDB currentOp command can be used to list queries that are either blocked or executing longer than a specified time.
Reference:
https://docs.aws.amazon.com/documentdb/latest/developerguide/user_diagnostics.html#user_diagnostics-query_terminating