Which of the following acts as biofertilizer in paddy field?

Azospirillum

The correct answer is Option (3) – Azospirillum

Azospirillum a plant growth-promoting bacteria is being used as biofertilizer in several countries of the world. It is a soil bacterium capable of producing associative symbiosis in the roots of various plants including grain crops including rice. Azospirillum promotes plant growth by fixing atmospheric nitrogen and by some other ways like production of growth promoting substances and influencing root development, causing increased uptake of nutrients from the land, and inhibiting pathogenic fungi and bacteria in the rhizosphere.