Which of the following statement(s) is/are correct?
I. The presence of a triploid endosperm nucleus is a distinctive feature of gymnosperms.
II. In gymnosperms, endosperm represents the female gametophyte.

The correct option is B Only II
The endosperm is the food-laden tissue which is meant for nourishing the embryo in seed plants. In gymnosperms, it represents the female gametophyte and thus is haploid.

In angiosperms, the endosperm is a unique tissue formed due to the fusion of a male with the central cell's diploid secondary nucleus (vegetative fertilization or triple fusion). The fusion product is the primary endosperm cell having a triploid (3n) endosperm nucleus.