Statement $P$: Single-cell protein is obtained through the process of fermentation.
Statement $Q$: Callus is maintained on agar-agar gel.

• A
  Both Statement $P$ and Statement $Q$ are incorrect.
• B
  Both Statement $P$ and Statement $Q$ are correct.
• C
  Statement $P$ is correct and Statement $Q$ is incorrect.
• D
  Statement $P$ is incorrect and Statement $Q$ is correct.