What is the issue?

Refer to the exhibit.

The NOC engineer noticed that the R2 router system clock is not updated and synchronized to the NTP server that is configured on the R10 router.

What is the issue?
A . The maximum number of peers and client associations is exceeded
B . The access list NTP_Clients is missing
C . The PE2 router should be configured as an NTP peer instead of as a client
D . The access group is misconfigured
E . The authentication key is mismatched

Answer: E