Read the following statements about the reproductive cycles in mammals and select the correct ones.
(i) Oestrous cycle occurs in primate mammals.
(ii) In species with oestrous cycle, females are generally sexually active during oestrous phase.
(iii)Both the cycles show monthly recurrence.

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (ii) only
D. (i), (ii) and (iii)

Explanation

To analyze the statements about reproductive cycles in mammals, we can break down the question step by step:

### Step-by-Step Solution:

1. **Understanding the Types of Reproductive Cycles**:
- There are two main types of reproductive cycles in mammals: the oestrous cycle and the menstrual cycle.
- The oestrous cycle is typically found in non-primate mammals, while the menstrual cycle occurs in primate mammals (including humans).

2. **Evaluating Statement (i)**:
- **Statement (i)**: "Oestrous cycle occurs in primate mammals."
- This statement is **incorrect** because the oestrous cycle is not found in primates; instead, primates have a menstrual cycle.

3. **Evaluating Statement (ii)**:
- **Statement (ii)**: "In species with oestrous cycle, females are generally sexually active during oestrous phase."
- This statement is **correct**. In species that experience the oestrous cycle, females are indeed sexually active during the oestrous phase (also known as heat).

4. **Evaluating Statement (iii)**:
- **Statement (iii)**: "Both the cycles show monthly recurrence."
- This statement is **incorrect**. The menstrual cycle does show a monthly recurrence (approximately every 28 to 30 days), but the oestrous cycle does not have a fixed monthly recurrence; it varies among species (e.g., it can be 15 days, 18 days, or even more).

5. **Conclusion**:
- The only correct statement is (ii). Therefore, the correct answer is that only statement (ii) is true.

### Final Answer:
- The correct statements about the reproductive cycles in mammals are: **(ii) only**.