In order for researchers to be able to say that variable a causes variable b, they must eliminate the possible influence of

a. correlational variables
b. independent variables
c. dependent variables
d. confounding variables

D.

Explanation:

Confounding variables can be termed as the variables not counted in for account. They are the 'extra' variables. Such variables can hamper the experiments and produce a useless result also.

Such variables causes the introduction of bias in an experiment and can increase the possibility of variances. And to avoid or to eliminate such possibilities, confounding variables should be avoided in research.

So, the correct answer is option D.

answer; the intervening variable;