Comparison Is Important in Social Research Because

Comparison is important in social research because

A) much research makes comparisons designed to test an "if ... then" statement.
B) values of the dependent variable that differ among categories of the independent variable imply some idea about causality, which requires comparison.
C) an "if ... then" comparison generally indicates the possibility of a cause-and-effect relationship.
D) all of these (a, b, c)