Darwin described the behavior of animals by using terms that denote human emotions and feelings, e.g., ants "despaired", dogs expressed "pleasure" and "love", etc. He did this because

A) he considered the minds of humans and animals to be similar in complexity.
B) he considered the minds of humans and animals to be similar in kind and to differ only in complexity.
C) he was an excellent theorist but not a very good scientist.
D) such explanations made his ideas more readily acceptable to the general population.