Consider the following regarding the reasons for the fact that now Cyanobacteria are kept in Monera and not in Plantae:

I. They are prokaryotes.
II. The cell wall of cyanobacteria has peptidoglycan.
III. They can fix atmospheric nitrogen.

The correct explanations would be:

1. I and II only
2. I and III only
3. II and III only
4. I, II and III