Directions : For the Assertion (A) and Reason (R) below, choose the correct alternative _x005F_x000D_ Assertion(A) :  A little gap is left between iron rails. _x005F_x000D_ Reason (R)  :  Iron expands in summer.

• 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.