An Environmental Sample from the Ocean Contains Phototrophic Bacteria That

An environmental sample from the ocean contains phototrophic bacteria that produce oxygen.How would you classify these bacteria?

A) Information about the cell wall would be required to determine whether these bacteria are Gram positive or Gram negative.
B) These bacteria must be cyanobacteria based on their production of oxygen.
C) It is highly probable that these bacteria are Gram-negative bacteria based on their presence in a marine environment.
D) These bacteria must be chlamydia found within unicellular organisms.