Assertion $(A)$: The speed of a body in uniform circular motion is constant.
Reason $(R)$: In uniform circular motion,the acceleration of the body is constant.

• A
  Both $(A)$ and $(R)$ are true and $(R)$ is the correct explanation of $(A)$.
• B
  Both $(A)$ and $(R)$ are true but $(R)$ is not the correct explanation of $(A)$.
• C
  $(A)$ is true but $(R)$ is false.
• D
  $(A)$ is false but $(R)$ is true.