Of the Following,the Best Description of "Intervening Variables" in Psychology

Multiple Choice

Of the following,the best description of "intervening variables" in psychology is that

A) they are constructs that unite a wide variety of apparently dissimilar variables.
B) they are obstacles in successful theory construction and testing.
C) there are very few intervening variables in psychology.
D) they rarely are of use when psychologists try to explain why variables are relateD.