Development of pollen grains occur in:

The correct answer is Option (1) → Microsporangium

The anther of a stamen has four microsporangia (pollen sacs). The cells at the centre of each one, called the sporogenous tissue, divide by meiosis (microsporogenesis) to give tetrads of microspores. Each microspore then matures into a pollen grain.

(1) Microsporangium — Correct. It is the male structure in which the pollen grains form.

(2) Megasporangium — Incorrect. This is the female structure, also called the ovule. It forms megaspores, not pollen grains.

(3) Ovule — Incorrect. It is the female structure that develops into the seed after fertilisation. It carries the megasporangium and the embryo sac.

(4) Embryo sac — Incorrect. It is the female gametophyte, which forms inside the ovule from the functional megaspore.

NCERT Extract:
Apomixis and Polyembryony – …