Pollen grains move from the anthers to the stigma, where they stick to the sticky stigma. The statements below show what occurs afterwards. 1. The pollen grain produces a pollen tube. 2. The pollen tube grows down the style. 3. The pollen tube enters the ovule. 4. The male nucleus joins with an egg cell nucleus. What is the correct sequence for these stages?
- A$1 \rightarrow 2 \rightarrow 4 \rightarrow 3$
- B$1 \rightarrow 3 \rightarrow 2 \rightarrow 4$
- C$2 \rightarrow 3 \rightarrow 1 \rightarrow 4$
- D$3 \rightarrow 1 \rightarrow 4 \rightarrow 2$