Statement $P$: The nomenclature of an organism is done by two names.
Statement $Q$: The species name is written in small letters.

• A
  Statement $P$ is true. Statement $Q$ is false.
• B
  Statement $Q$ is true. Statement $P$ is false.
• C
  Statement $P$ and $Q$ are true and $Q$ is not the correct explanation of $P$.
• D
  Statement $P$ and $Q$ are true and $Q$ is the correct explanation of $P$.