Statement $A$: Plant cells lack centrioles.
Statement $R$: Plant cells form a bipolar spindle during cell division.

• A
  $A$ and $R$ are both true,$R$ is not the correct explanation of $A$.
• B
  $A$ and $R$ are both false.
• C
  $A$ and $R$ are both true,$R$ is the correct explanation of $A$.
• D
  $A$ is false and $R$ is true.