Refer to the exhibit. 

A customer has an IPsec tunnel that is configured between two remote offices. The customer is seeing these syslog messages on Router B: %CRYPTO-4-PKT_REPLAY_ERR: decrypt: replay check failed connection id=x, sequence number=y What is the most likely cause of this error? 

Answer options:

A. The customer has an LLQ QoS policy that is configured on the WAN interface of Router A.B. A hacker on the Internet is launching a spoofing attack.
C. Router B has an incorrectly configured IP MTU value on the WAN interface.
D. There is packet corruption in the network between Router A and Router
B.E. Router A and Router B are not synchronized to the same timer source.

A