Diploid cells have :
(a) One set of chromosomes
(b) Two sets of chromosomes
(c) Two pairs of homologous chromosomes
(d) Two chromosomes

Options

A. One set of chromosomes
B. Two sets of chromosomes
C. Two pairs of homologous chromosomes
D. Two chromosomes

Answer

To solve the question regarding diploid cells, let's analyze each option step by step:

1. **Understanding Diploid Cells**:
- Diploid cells are characterized by having two complete sets of chromosomes. This means that for each type of chromosome, there are two copies: one inherited from the mother and one from the father.

2. **Analyzing Option (a) One set of chromosomes**:
- This option refers to haploid cells, which have only one set of chromosomes (n). Therefore, this option is incorrect for diploid cells.

3. **Analyzing Option (b) Two sets of chromosomes**:
- This option correctly describes diploid cells, which are denoted as 2n. Here, "2" indicates that there are two sets of chromosomes (one from each parent). Thus, this option is correct.

4. **Analyzing Option (c) Two pairs of homologous chromosomes**:
- While diploid cells do contain pairs of homologous chromosomes, stating "two pairs" is misleading because diploid cells can have more than two pairs depending on the organism. Therefore, this option is not a comprehensive description of diploid cells.

5. **Analyzing Option (d) Two chromosomes**:
- This option is misleading because it implies that diploid cells only have two chromosomes in total, which is incorrect. Diploid cells have multiple chromosomes, typically in pairs. Therefore, this option is also incorrect.

6. **Conclusion**:
- The correct answer is (b) Two sets of chromosomes.

### Summary of the Correct Answer:
The correct option is (b) Two sets of chromosomes, as diploid cells are defined by having two complete sets of chromosomes (2n).