The pupil of the eye expands as much as 45 percent when a person looks at something pleasing.
A
Correct answer
Explanation
The pupil can expand by up to 45% when viewing something pleasing due to the pupillary dilation response. This physiological reaction is part of the autonomic nervous system's response to emotional or cognitive stimuli. The expansion allows more light to enter the eye and is controlled by the iris muscles. This phenomenon is used in psychology and marketing research to measure genuine interest and emotional response.