The sunshine colored the flowers yellow. The flowers of the parent plants were yellow. It was very warm when they flowered. It rained every day.
A plant has yellow flowers. What best explains why the flowers are yellow?

Options:
- The sunshine colored the flowers yellow.
- The flowers of the parent plants were yellow.
- It was very warm when they flowered.
- It rained every day.

The flowers of the parent plants were yellow.