The species of which of the following kinds of organisms are generally used as biofertilizers?
1. Blue-Green Algae
2. Spirogyra
3. Nostoc
4. Alfa-alfa
Select the correct answer using the codes given below:
1
1, 2, 3 and 4
2
1 and 3
3
1, 2 and 4
4
2, 3 and 4