(A) : Small animals have a larger surface area relative to their volume.
(R) : They tend to lose body temperature very slowly when it is cold out side.
A. If both (A) and (R) are true but (R) is not the correct explanation of (A).
B. If both (A) and (R) are true and (R) is the correct explanation of (A).
C. If (A) is true but (R) is false.
D. If both (A) and (R) are false.