Aflatoxin is:
a) the loss of an amino group on a nitrogenous base.
b) the gain of an amino group on a nitrogenous base.
c) an artificial mutagen.
d) another name for unmethylated cytosine.
e) a natural mutagen.

E) a natural mutagen.

Explanation:

Aflatoxin is a toxin byproduct produced by the fungi especially Aspergillus molds which grows attached to the roots of various crops like the peanuts, wheat and many others.

The aflatoxin is considered a carcinogen and a mutagen as it causes certain changes in the structure of DNA.  The aflatoxin mainly affects the liver and causes a mutation in the genes of the liver and since the aflatoxin is produced naturally by the molds, therefore, is considered a natural mutagen.

Thus, option-E is correct.