The correct answer to this question was not provided. The provided answer is "5", but there is no option with this number.

However, let`s dissect the statements to determine which ones are correct:

1. Stamen is present in the center of a flower.

- This statement is true. The stamen is the male reproductive organ of a flower and is typically found in the center.

2. Stamen produces pollen grains in the ovary.

- This statement is incorrect. The stamen produces pollen grains in the anther, which is part of the stamen, but not in the ovary.

3. The swollen bottom part of the carpel is the ovary.

- This statement is true. The carpel is the female reproductive organ of a flower, and the ovary is the swollen base of the carpel that contains the ovules.

4. The fusion of germ cells gives rise to the zygote.

- This statement is true. During sexual reproduction in flowering plants, the sperm cell from the pollen grain fuses with the egg cell in the ovary to form a zygote.

Therefore, the correct options would be:

- Option 1: 2, 3, and 4 only.

Alert - correct answer should