Select the correct option of haploid cells from the following groups :

Options

A. Primary oocyte, Secondary oocyte, Spermatid
B. Secondary spermatocyte, First polar body, Ovum
C. Spermatogonia, Primary spermatocyte, Spermatid
D. Primary spermatocyte, Secondary spermatocyte, Second polar body

Answer

To determine the correct option of haploid cells from the given groups, we need to analyze each option based on the ploidy level of the cells mentioned.

### Step-by-Step Solution:

1. **Understanding Haploid and Diploid Cells**:
- **Haploid (n)**: Cells that contain one set of chromosomes. Examples include gametes (sperm and egg).
- **Diploid (2n)**: Cells that contain two sets of chromosomes. Examples include somatic cells and germ cells like primary oocytes and spermatogonia.

2. **Analyzing the Options**:
- **Option 1**: Primary oocyte, secondary oocyte, spermatid.
- Primary oocyte: Diploid (2n)
- Secondary oocyte: Diploid (2n)
- Spermatid: Haploid (n)
- **Conclusion**: This option is incorrect as it contains diploid cells.

- **Option 2**: Secondary spermatocyte, 1st polar body, ovum.
- Secondary spermatocyte: Haploid (n)
- 1st polar body: Haploid (n)
- Ovum: Haploid (n)
- **Conclusion**: This option is correct as all three are haploid cells.

- **Option 3**: Spermatogonia, primary spermatocyte, spermatid.
- Spermatogonia: Diploid (2n)
- Primary spermatocyte: Diploid (2n)
- Spermatid: Haploid (n)
- **Conclusion**: This option is incorrect as it contains diploid cells.

- **Option 4**: Primary spermatocyte, secondary spermatocyte, 2nd polar body.
- Primary spermatocyte: Diploid (2n)
- Secondary spermatocyte: Haploid (n)
- 2nd polar body: Haploid (n)
- **Conclusion**: This option is incorrect as it contains a diploid cell.

3. **Final Conclusion**:
- The correct option containing only haploid cells is **Option 2**: Secondary spermatocyte, 1st polar body, ovum.