What Is the Primary Limitation of Using Only Two Levels

Multiple Choice

What is the primary limitation of using only two levels of a factor in a two-factor between-subjects design?​

A) ​It is simple to interpret.
B) ​It increases the chances of demonstrating a significant mean difference.
C) It tends to reduce the differences between the groups.
D) ​It may not provide a complete picture of how the factor affects the dependent variable.