(A) Assertion - A mammal has double circulation.
(R) Reason - Higher energy needed by warm blooded animal.
a. Both (A) and (R) are correct and (R) is the correct explanation of (A).
b. Both (A) and (R) are correct 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.