Which of the Following Conditions Should Not Necessarily Be Met

Multiple Choice

Which of the following conditions should not necessarily be met to establish that a change in the independent variable causes a change in the dependent variable:

A) The independent and the dependent variable should co-vary: in other words,a change in the dependent variable should be associated with a change in the independent variable.
B) The independent variable (the presumed causal factor) should precede the dependent variable.In other words,there must be a time sequence in which the two occur: the cause must occur before the effect.
C) No other factor should possibly cause the change in the dependent variable.Hence,the researcher should control for the effects of other variables.
D) A third variable should modify the original relationship between the independent and the dependent variable.