Which of the following statements are true for flowers?
(i) Flowers are always bisexual
(ii) They are the sexual reproductive organs
(iii) They are produced in all groups of plants
(iv) After fertilisation they give rise to fruits

Options

A. (i) and (iv)
B. (ii) and (iii)
C. (i) and (iii)
D. (ii) and (iv)

Explanation

To determine which statements about flowers are true, let's analyze each statement one by one:

1. **Statement (i): Flowers are always bisexual.**
- This statement is **false**. While many flowers are bisexual (containing both male and female reproductive structures), there are also unisexual flowers that contain only male or only female reproductive structures. Therefore, this statement is incorrect.

2. **Statement (ii): They are the sexual reproductive organs.**
- This statement is **true**. Flowers are indeed the sexual reproductive organs of angiosperms (flowering plants). They facilitate sexual reproduction by producing gametes and enabling fertilization. Thus, this statement is correct.

3. **Statement (iii): They are produced in all groups of plants.**
- This statement is **false**. Flowers are specifically produced by angiosperms. Other groups of plants, such as bryophytes, pteridophytes, and gymnosperms, do not produce flowers. Therefore, this statement is incorrect.

4. **Statement (iv): After fertilization, they give rise to fruits.**
- This statement is **true**. After fertilization occurs in flowers, the ovary develops into a fruit, and the ovule develops into a seed. This is a fundamental aspect of the reproductive process in flowering plants. Hence, this statement is correct.

Based on the analysis:
- **True Statements**: (ii) and (iv)
- **False Statements**: (i) and (iii)

Thus, the correct answer is that statements (ii) and (iv) are true for flowers.

### Final Answer:
The true statements for flowers are (ii) and (iv).