In a fertilised embryo sac, the haploid, diploid and triploid structures are

Options

A. synergid, zygote and primary endosperm nucleus
B. synergid, antipodal and polar nuclei
C. antipodal, synergid and primary endosperm nucleus
D. synergid, polar nuclei and zygote

Answer

To solve the question regarding the haploid, diploid, and triploid structures in a fertilized embryo sac, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding the Structure of the Embryo Sac**:
- The embryo sac is the female gametophyte of flowering plants and contains several types of cells, including the egg cell, synergids, polar nuclei, and antipodal cells.

2. **Identifying the Ploidy of Cells in the Embryo Sac**:
- The egg cell and synergids are haploid (N).
- The antipodal cells are also haploid (N).
- The central cell contains two polar nuclei, which are each haploid (N), thus making the central cell diploid (N + N) before fertilization.

3. **Fertilization Events**:
- During fertilization, the egg cell fuses with a male gamete (which is also haploid), resulting in the formation of a zygote, which is diploid (2N).
- The central cell undergoes triple fusion with another male gamete, resulting in the formation of the primary endosperm nucleus, which is triploid (3N).

4. **Summarizing the Ploidy of Structures**:
- **Haploid Structures**: Synergids, egg cell, antipodal cells, and polar nuclei (before fertilization).
- **Diploid Structure**: Zygote (after fertilization of the egg cell).
- **Triploid Structure**: Primary endosperm nucleus (after fertilization of the central cell).

5. **Final Answer**:
- In a fertilized embryo sac:
- Haploid structures: Synergids, egg cell, antipodal cells, polar nuclei.
- Diploid structure: Zygote.
- Triploid structure: Primary endosperm nucleus.

### Conclusion:
The correct answer to the question is:
- **Haploid**: Synergids, egg cell, antipodal cells, polar nuclei.
- **Diploid**: Zygote.
- **Triploid**: Primary endosperm nucleus.