The behaviorist B. F skinner was a __ when it came to explaining how children learn language

 nurturist

Explanation:

The American psychologist and behaviorist Burroughs Frederick Skinner ( 1904 – 1990)  was a Harvard Professor of Psychology. He is considered the pioneer of modern behaviorism. He explained in his book “Behavior of Organisms “  how environmental variables control behavior. He believed that parents’ nurturing shape the child’s language behavior.

i am positive it is c. condensing but i may be wrong