Answer:
The correct answer is B. confounding variable
Step-by-step explanation:
A researcher conducts a study examining the alcohol consumption of college students. She brings the first group of students into the laboratory the week before spring break. She brings the second group of students into the laboratory the week after spring break. The difference in timing of the two groups may be a CONFOUNDING VARIABLE
A confounding variable is an outside influence that changes the effect of a dependent and independent variable. This extraneous influence is used to influence the outcome of an experimental design. Simply, a CONFOUNDING VARIABLE is an extra variable entered into the equation that was not accounted for.