Leafy Greens Are Generally Quite Nutritious

Leafy greens are generally quite nutritious. What do leaves do for plants that would require them to be full of biochemicals?

A) Leafy greens aren't really all that nutritious but they provide fiber for the plant so they're good for you to eat for digestive purposes.
B) Leaves absorb a lot of vitamins and minerals from the sun.
C) Leaves are the primary site for energy storage in most plants.
D) Xylem and phloem end in the leaves which then act as storehouses for water and nutrients.
E) Leaves are where photosynthesis mostly occurs, so the building blocks for energy (and therefore, food) must all be there.