Assertion (A) : Bats and whales are classified as mammals.
Reason (R) : Bats and whales have a four-chambered heart.

• 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

  Both A and R are false.