Which of the following statements best describes pollination in plants?

Pollination is the transfer of pollen grains from the anther, which is the male part of the flower where pollen is made, to the stigma, which is the sticky top of the female part (the carpel or pistil). Wind, water, insects, birds or even humans can carry the pollen across.

The direction matters. Saying pollen moves from the stigma to the anther is backwards — the stigma receives pollen, it does not produce it. So that option describes something that never happens.

Pollination is also not the same as seed formation. After the pollen lands on the stigma, it grows a pollen tube down to the ovule and fertilisation happens; only then does a seed form. Pollination is the delivery step that comes before fertilisation, not the seed-making itself.

Simply releasing pollen into the air is only part of the journey. Until that pollen actually lands on a stigma, pollination has not taken place. That is why the anther-to-stigma transfer is the correct description.