Correct Answer: A
The command that results in these messages when attempting to troubleshoot an iPsec VPN connection is debug crypto isakmp. This command displays debug information about the Internet Key Exchange (IKE) protocol, which is used to establish security associations (SAs) for IPsec VPNs. The messages in the exhibit show various steps and statuses of the IKE negotiation process, such as creating and deleting peer structures, receiving and sending packets, and checking the compatibility of the security policies and proposals. The other commands are either invalid (debug crypto ipsec endpoint and debug crypto isakmp connection) or display different information (debug crypto ipsec shows the details of the IPsec encryption and decryption operations). References:
https://www.cisco.com/c/en/us/training-events/training-certifications/training/training-services/courses/implemen
https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/5409-ipsec-debug-00.h