Antibiotic resistance in bacteria is the result of
a) binary fission.
b) nitrogen fixation
c) genetic variation.
d) genetic engineering.

C. Genetic variation

Bacteria are very numerous,  and random mutation of bacterial DNA generates a wide variety of change, including resistance. It happens through mutation and selection. Not only are they capable of sharing genetic bits of DNA to related and unrealted species they can develop ways to remove the antibiotic before it reaches its intended area via biochemical pumps or enzymes to inactiavte the antibiotic.

Ithink the answer is d.