Answer:
The correct answer is option C, that is, anaerobic chemoheterotroph.
Step-by-step explanation:
Chemoautotrophs refer to the organisms, which can produce energy by oxidation of inorganic components found in the environment. They utilize inorganic components as the source of energy. They produce organic compounds by fixing carbon dioxide from the surrounding.
On the other hand, chemoheterotrophs consume and digest organic components from the surroundings. However, they use inorganic compounds as a source of energy. The intestinal bacterium attains its carbon sources by digesting the food components found in the intestine. Thus, it is most probably a chemoheterotroph as it can dissociate down the organic compounds found in the food.
The mentioned bacteria are anaerobic in nature, as it can survive easily in an extremely harsh environment of intestines, and are also resistant to high temperatures.