Answer:
D. Clostridium does not have enzymes to process toxic oxygen
Explanation:
Obligate anaerobes are microorganisms killed by normal atmospheric concentrations of oxygen (20.95% O2). Oxygen tolerance varies between species, some capable of surviving in up to 8% oxygen, others losing viability unless the oxygen concentration is less than 0.5%. in other words, Obligate anaerobes are organism which can only live in environments which lack oxygen. Unlike the majority of organisms in the world, these organisms are poisoned by oxygen.
Therefore clostridium do not have enzymes to process this oxygen which is toxic for it