Assertion (A): Only one sperm can fertilise an ovum. Reason (R): During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that block the entry of additional sperms. Regarding (A) and (R):

Question

( A ) A is incorrect but R is correct
( B ) Both A and R are correct & R is the correct explanation for A
( C ) A is correct but R is incorrect
( D ) Both A and R are correct but R is not the correct explanation for A