Answer:
A - Absolute threshold.
Explanation:
As the exercise briefly states, an absolute threshold is the point at which a person can detect a stimulus 50 percent of the time. Be it sound, touch, sight, taste and smell, the absolute threshold is the smallest level of stimulus to be detected, said to be at least 50 percent of the time. A common example to test the absolute threshold, in this case the hearing threshold, could be to place a person 20 feet away from a clicking clock.