Refer to the exhibit. An administrator noticed that after a change was made on R1, the timestamps on the system logs did not match the clock. What is the reason for this error? 

Answer options:

A. An authentication error with the NTP server results in an incorrect timestamp.
B. The keyword localtime is not defined on the timestamp service command.
C. The NTP server is in a different time zone.
D. The system clock is set incorrectly to summer-time hours.

A