Techniques Such as Meta-Analysis Are Useful in Psychology Because

Techniques such as meta-analysis are useful in psychology because:

A) they help reduce unintended changes in subjects' behaviour due to cues given by the experimenter.
B) they allow for the careful study of behaviour in schools, workplaces, and other natural contexts.
C) they provide a range of values within which the mean of a population is likely to lie.
D) rarely does one study alone prove anything, and this technique analyzes data from many studies.