A fundamental assumption of Festinger's social comparison theory is that people

A) compare different societies to find ways to improve their own.
B) have a need for novelty and change.
C) have a need to evaluate their beliefs and attitudes.
D) have a need for power and try to control the behavior of others.
E) compare the various groups that they belong to.

Festinger's social comparison theory asserts that people engage in social comparison to evaluate their beliefs and attitudes, as well as to reduce uncertainty about themselves and their social world. Therefore, option C is the most appropriate choice. Option A is incorrect because the theory deals with individual level comparisons, not societal ones. Option B implies that the need for novelty and change drives social comparison, which is not what the theory suggests. Option D involves a separate concept of social control, which is not related to social comparison theory. Option E is partially correct, but the theory's emphasis is on intra-group comparison rather than inter-group comparison.