Every Time a User Boots-Up Their Computer, They Notice the System

Every time a user boots-up their computer, they notice the system date is incorrect during the boot-sequence. Once the computer loads into Windows, however, the date corrects itself. What is likely the issue?

A) The computer's power supply needs to be replaced.
B) Windows is corrupt and must be reinstalled.
C) The BIOS is corrupt and must be flashed.
D) The CMOS battery needs to be replaced.