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

Explanation

To answer the question about the haploid, diploid, and triploid structures in a fertilized embryo sac, we can break down the components involved in the fertilization process and the structures formed.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- In a fertilized embryo sac, there are several key structures:
- **Synergids**: These are two cells located near the micropyle of the embryo sac. They are haploid (n).
- **Antipodals**: These are three cells located at the opposite end of the embryo sac. They are also haploid (n).
- **Central Cell (Polar Nuclei)**: This is the cell that contains two polar nuclei and is diploid (2n).
- **Zygote**: This is formed from the fusion of male and female gametes and is diploid (2n).
- **Primary Endosperm Nucleus**: This is formed by the fusion of one male gamete with the central cell (which has two polar nuclei) and is triploid (3n).

2. **Identifying the Structures**:
- **Haploid Structures**:
- Synergids (n)
- Antipodals (n)
- **Diploid Structures**:
- Zygote (2n)
- Central Cell (2n)
- **Triploid Structure**:
- Primary Endosperm Nucleus (3n)

3. **Conclusion**:
- The correct identification of the structures in a fertilized embryo sac is:
- **Haploid**: Synergids (n)
- **Diploid**: Zygote (2n)
- **Triploid**: Primary Endosperm Nucleus (3n)

### Final Answer:
In a fertilized embryo sac, the haploid, diploid, and triploid structures are:
- **Haploid**: Synergids (n)
- **Diploid**: Zygote (2n)
- **Triploid**: Primary Endosperm Nucleus (3n)