Legumes fails to develop nodule if pH is less than

Answer: Option B

Legumes are the plants that form roots nodules in association with the rhizobium bacteria. The free-living soil bacteria grows near the roots of the legumes and is unable to fix nitrogen in a free condition.
The formation of nodules is more sensitive to soil acidity than other aspects of plants. Legumes fail to develop nodules if pH is less than 5.