McClelland investigated three needs:

A. Safety, love, and esteem.

B. Growth, existence, and relatedness.

C. Power, persuasion, and persistence.

D. Affiliation, love, and relatedness.

E. Achievement, affiliation, and power.

E - Achievement, affiliation, and power.

Explanation:

David McClelland has been studying the relationship between needs and behavior since the late 1940s. Although he is most recognized for his research on the need for achievement, he also investigated the needs for affiliation and power. This is developed in his theory of the human motivation.