Alfalfa and Clover Are Two Legumes Commonly Planted as Cover

Alfalfa and clover are two legumes commonly planted as cover crops after the cash crop is harvested.Besides providing roots that will help keep soil in place,what would make these plants good cover crops?

A) Being legumes,they have a symbiosis with nitrogen-fixing bacteria to add nitrogen to the soil.
B) They are easily mowed,which adds less work to the farmers in the spring.
C) Their flowers attract bees,which will help the cash crops grow in the future.
D) Alfalfa is another cash crop that can be harvested and sold for food.
E) They use up any leftover fertilizer.