Which among the following statements about biofertilisers are correct?
1. Azotobacter is one of the nitrogen fixing bacteria used as biofertilisers.
2. They have to be applied to the leaves of the plants only.
3. They alter the chemical composition of the soil.
4. They can be used along with organic fertilisers.

A. 1 and 4

B. 1, 2 and 4

C. 2 and 3

D. All of these

Answer: Option A