A person taking a polygraph test is suspected of lying when measures of physiological variables such as heart rate and perspiration are:

A) higher for control questions than for test questions.
B) higher for test questions than for control questions.
C) evenly high for test questions and control questions.
D) unchanging for test questions and control questions.

Polygraph tests operate on the premise that when a person is lying, they exhibit physiological responses that differ from when they are telling the truth. Control questions are typically neutral in nature and designed to establish baseline physiological responses for comparison. Test questions are directly related to the matter under investigation. If a person's physiological responses (such as heart rate and perspiration) are higher for test questions than for control questions, it suggests that the person may be experiencing stress or anxiety associated with deception, leading to the suspicion of lying.