Explanation
The correct answer is (B) Nucellus.
In gymnosperms, such as Pinus, the ovule contains a megasporangium which is surrounded by one or more protective layers, including an integument. The nucellus is the central part of the megasporangium, and it contains the female gametophyte (embryo sac) and the egg cell.
After fertilization, the zygote develops into an embryo, and the nucellus and integument form the seed coat that surrounds the embryo and the endosperm. The membranous layer between the edible part (the endosperm) and the seed coat of Pinus seed is a remnant of the nucellus.
