$P -$ Statement: Interphase can be divided into three sub-phases.
$Q -$ Statement: The $G_1$ phase is the initial phase of interphase.

• A
  Both statements $P$ and $Q$ are correct.
• B
  Statement $Q$ is incorrect and statement $P$ is correct.
• C
  Both statements $P$ and $Q$ are correct,but statement $Q$ is not the correct explanation of statement $P$.
• D
  Both statements $P$ and $Q$ are incorrect.