Why is the correct configuration of a system's time zone important?

A. Because the conversion of Unix timestamps to local time relies on the time zone configuration.
B. Because the time zone is saved as part of the modification times of files and cannot be changed after a file is created.
C. Because the environment variables LANG and LC_MESSAGES are, by default, set according to the time zone.
D. Because NTP chooses servers nearby based on the configured time zone.