Arrange the following developmental stages during the formation of the embryo sac in the correct sequence:

Archesporium → Megaspore mother cell → Megaspore → Embryo sac.

The correct sequence of developmental stages during the formation of the embryo sac is:

(b) Archesporium → Megaspore mother cell → Megaspore → Embryo sac.

Explanation:

1. Archesporium: A single celled archesporium differentiates in the internal cells of nucellus near the micropylar end.
2. Megaspore mother cell : The archesporial cell may directly function as megaspore mother cell.
3. Megaspore: The megaspore mother cell undergoes meiosis to form four haploid megaspores. Among the four megaspores, only one is functional and capable of developing into the female gametophyte, known as the embryo sac. The other three megaspores typically degenerate or undergo programmed cell death.
4. Embryo sac: The surviving megaspore undergoes mitotic divisions and cellular differentiations to develop into the embryo sac, which is the female gametophyte. The embryo sac consists the egg cell, synergids, antipodal cells, and central cell. This process of embryo sac formation from a single megaspore is referred to as monosporic development. It is a common mechanism in the majority of flowering plants.

Therefore, the correct sequence is (b) Archesporium → Megaspore mother cell → Megaspore → Embryo sac.