Answer:
c) symbiotic
Step-by-step explanation:
-There is a symbiotic relationship between the legumes which contains root nodules and Rhizobium bacteria.
-Rhizobia live in the soil.
-When there is limited soil nitrogen, legumes in symbiotic relationship release flavanoids which sends signal to rhizobia that the plant needs symbiotic bacteria.
-Rhizobia produces ammonia from the atmospheric nitrogen and assists the plant's growth.