Answer - B.
The AWS Documentation mentions the following.
AWS Lambda is integrated with AWS CloudTrail, a service that captures API calls made by or on behalf of AWS Lambda in your AWS account and delivers the log files to an Amazon S3 bucket that you specify.
CloudTrail captures API calls made from the AWS Lambda console or from the AWS Lambda API.
Using the information collected by CloudTrail, you can determine what request was made to AWS Lambda, the source IP address from which the request was made, who made the request, when it was made, and so on.
Option A is incorrect since this can only give information on the logs from Cloudwatch but not who called the Lambda function itself.
Option C is incorrect since this is used for logging network traffic to the VPC.Option D is incorrect since this cannot give API logging information.
