Effective Research on Personality Requires Two Kinds of Efforts or Approaches

Effective research on personality requires two kinds of efforts or approaches. They are

A) classifying people into certain groups, and distinguishing the features of the groups.
B) identifying personality characteristics, and determining the variables that produce and control them.
C) relating information learned from animal models, and distinguishing the differences between those models and different human populations.
D) measuring the differences in personalities between people, and relating those data to the development of specific types of personality traits.
E) classifying people into certain groups, and distinguishing the differences between those models and different human populations.