Aprokaryote is most likely to use which of the following modes of metabolism to release energy if it is in an environment without oxygen, dies when exposed to oxygen, and uses fermentation?

a. photoautotroph
b. facultative anaerobe
c. obligate anaerobe
d. heterotroph < is the right answer

Most heterotrophs are chemoorganoheterotrophs (or simply organotrophs) who utilize organic compounds both as a carbon source and an energy source. The term "heterotroph" very often refers to chemoorganoheterotrophs. Heterotrophs function as consumers in food chains: they obtain organic carbon by eating autotrophs or other heterotrophs. Most opisthokonts and prokaryotes are heterotrophic

The right answer to this question is D. Heterotroph