A Bacterium That You Isolated from Pond Water Appears to Use

A bacterium that you isolated from pond water appears to use light for energy. Based upon this information, you inoculate the organism into fresh media, infused with lots of carbon dioxide. Even after incubation at the correct temperature (of pond water) , the organism is not growing. Your best
Explanation of what might have happened is _______.

A) there was no sulfur compound added to the medium, that could be used as an electron donor
B) no oxygen was added to the medium so the organism died
C) there is some inhibitory chemical that is preventing the growth of the bacterium
D) you were using the wrong type of sunlight as the energy source for the bacterium