Which of the following are the three main parts of a flower?

The correct answer encompasses the three main parts of a flower, which are essential for its reproductive function. Flowers typically consist of sepals, petals, and reproductive organs, which include stamens (the male reproductive parts) and pistils (the female reproductive parts).

Sepals serve as protective coverings for the flower when it is still a bud, while petals attract pollinators with their vibrant colors and patterns. The reproductive organs facilitate the process of pollination and fertilization, allowing for the production of seeds. In combination, these elements are crucial in completing the life cycle of flowering plants and ensuring their reproduction.

The other options refer to components that are either not part of the flower (like leaves and roots) or do not accurately represent the main parts as defined in botanical terms. This makes the option involving sepals, petals, and the reproductive organs the most comprehensive and accurate representation of a flower's structure.