The common biofertilizers used in organic farming are

1. margosa
2. pyrethrum
3. green manure
4. nitrogen fixing bacteria and cyanobacteria

Correct Answer: (d) nitrogen-fixing bacteria and cyanobacteria

Explanation:

Living organisms are used in biofertilizers.

The common biofertilizers used in organic farming are nitrogen-fixing bacteria and cyanobacteria.