The phenomenon, where dark forms of moths become more prevalent than light forms in industrialized areas, is known as

industrial melanism

Explanation:

The phenomenon being described is known as industrial melanism. Like mentioned, this refers to the prevalence of darker colored varieties of different animals (especially moths) in more industrial areas which allow them to better camouflage themselves as opposed to their lighter-colored relatives. The ability to better camouflage themselves ultimately keeps them alive long enough to reproduce and pass on the prevalent gene to the next generation.

the right answer is a

the correct answer is d