The correct option is B Sunn hemp
Crotalaria juncea, known as sunn or sunn hemp, is a tropical Asian plant of the legume family (Fabaceae). It is generally considered to have originated in India. It is now widely grown throughout the tropics and subtropics as a source of green manure, fodder and lignified fiber obtained from its stem. Sunn hemp is also being looked at as a possible bio-fuel. It is most commonly used as green manure in India. Sunflower, sesame and pigeon pea are not used as green manure. Thus, option B is correct.