Assertion (A) Leguminous plants are nitrogen fixers.
Reason (R) Leguminous plants have Rhizobium in their root nodules.

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true, but R is not the correct explanation of A

C. A is true, but R is false

D. A is false, but R is true

Answer: Option A