The correct option is A the ability to perform oxygenic photosynthesis due to the presence of chlorophyll a
Cyanobacteria undergo oxygenic photosynthesis. This means they use water as an electron donor. Splitting of this water results in liberation of oxygen. Cyanobacteria use chlorophyll a for oxygenic photosynthesis. In anoxygenic photosynthesis, there is no release of oxygen as water is not the electron donor.