Embryo sac in angiosperms:

- The female gametophyte in angiosperms is called the embryo sac.
- It develops inside the ovule, which is located in the ovary of the flower.
- The embryo sac is formed from a single haploid megaspore that undergoes three rounds of mitotic divisions to produce eight haploid nuclei.
- These nuclei are arranged in a specific way to form the mature embryo sac.

Structure of a typical angiosperm embryo sac:

- At maturity, a typical angiosperm embryo sac is 8-nucleate and 7-celled.
- The eight nuclei are arranged in the following way:

1. Three nuclei at the micropylar end:

- These are located close to the opening of the ovule.

2. Three nuclei at the chalazal end:

- These are located towards the base of the ovule.

3. Two polar nuclei in the center:

- These are located in the center of the embryo sac, between the micropylar and chalazal ends.

- The seven cells are formed by the arrangement of the eight nuclei:

1. The egg cell:

- This is located at the micropylar end.
- It is formed by the fusion of one of the polar nuclei with a sperm cell during double fertilization.

2. Two synergids:

- These are located at the micropylar end.
- They play a role in guiding the pollen tube towards the egg cell.

3. Three antipodal cells:

- These are located at the chalazal end.
- Their function is not well understood.

4. The central cell:

- This is formed by the fusion of the two polar nuclei.
- It contains two polar nuclei and plays a role in the formation of the endosperm after fertilization.

- The mature embryo sac plays a crucial role in the sexual reproduction of angiosperms.

Embryo sac is the female gametophyte of angiosperms which develops inside the ovule. It is formed by the process of megasporogenesis and megagametogenesis.

Structure of Angiosperm Embryo Sac:
- The mature embryo sac has a large central cell with two polar nuclei.
- Three antipodal cells are present at the opposite end of the central cell.
- At the micropylar end, there are two synergids that flank the egg cell.

Maturity of Angiosperm Embryo Sac:
- At maturity, the embryo sac is 8-nucleate and 7-celled.
- The two polar nuclei in the central cell have fused to form a secondary nucleus.
- The egg cell is present at the micropylar end, flanked by two synergids.
- Three antipodal cells are present at the opposite end of the central cell.
- The embryo sac is surrounded by an integument which later forms the seed coat.

Option C is the correct answer because it mentions the correct number of nuclei and cells present in a mature angiosperm embryo sac.