Physiological Instruments Such as a Pupillometric Meter and Psychogalvanometer Are

Physiological instruments such as a pupillometric meter and psychogalvanometer are used in advertising research to measure physiological reactions to ads because researchers believe that

A) they give an accurate measure of a person's physiological reaction to ads
B) they are cheaper and more efficient method of research than paper-and-pencil surveys
C) they are more accurate at measuring a person's reaction to ads than paper-and-pencil surveys
D) they are a good form of collecting qualitative data