The correct answer is b) stigma. The stigma is a part of the pistil, which is the female reproductive structure of a flowering plant. Its main function is to trap pollen grains. To arrive at this answer, you can use your knowledge about the different parts of a flower. Familiarize yourself with the structure of a flower, including the pistil, which consists of three main parts: the stigma, the style, and the ovary. Each part has a specific function in the reproduction of the plant. In this case, knowing that pollen is trapped by the stigma will lead you to the correct answer.
