Which of the following statements about sexual reproduction in flowering plants are correct? 1. Stamen is present in the centre of a flower. 2. Stamen produces pollen grains in the ovary. 3. The swollen bottom part of carpel is the ovary. 4. The fusion of germs cells gives rise to zygote. Select the correct answer using the code given below.

• A. 2, 3 and 4 only.
• B. 2 and 4 only.
• C. 1 and 3 only.
• D. 1, 2, 3 and 4