The bacterium, which is able to survive in both aerobic as well as anaerobic conditions are known as facultative anaerobes.
The facultative anaerobes are the organism, which can use oxygen for the synthesis of the ATP (adenosine triphosphate) molecule, but in the condition, where the oxygen is less or absent, they shift to fermentation or anaerobic respiration.
Hence, the correct answer is facultative anaerobes.