(a): the endosperm of gymnosperms is haploid.
(b) : megaspore is the mother cell of endosperm in gymnosperms.
(a) If both A and Rare true and Ris a correct explanation of A
(b) lf both A and Rare true but Ris not a correct explanation of A
(c) If A is true but Ris false
(d) If A is false but R may be true/false