What should a sysops administrator use to validate the calls mode to SQS?

A company received its latest bill with a large increase in the number of requests against Amazon SQS as compared to the month prior. The company is not aware of any major changes in its SQA usage. The company is concerned about the cost increase and who or what was making these calls.

What should a sysops administrator use to validate the calls mode to SQS?
A . Amazon CloudWatch
B . Amazon S3 server access logs
C . AWS CloudTrail
D . AWS Cost Explorer

Answer: A