What is Amazon CloudWatch?

What is Amazon CloudWatch?
A . A code repository with customizable build and team commit features.
B . A metrics repository with customizable notification thresholds and channels.
C . A security configuration repository with threat analytics.
D . A rule repository of a web application firewall with automated vulnerability prevention features.

Answer: B

Explanation:

Amazon CloudWatch is basically a metrics repository. An AWS service ― such as Amazon EC2 ― puts metrics into the repository, and you retrieve statistics based on those metrics. If you put your own custom metrics into the repository, you can retrieve statistics on these metrics as well.

Reference: https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_architecture.html