According to Hans Selye, resistance to stress is lowest at the __________ stage of the general adaptation syndrome.

A) alarm
B) resistance
C) exhaustion
D) collapse

The general adaptation syndrome is a three-stage physiological response to stress proposed by Hans Selye. The first stage is the alarm stage, in which the body reacts to stress with the fight-or-flight response. The second stage is the resistance stage, in which the body attempts to adapt to and cope with the stressor. The third and final stage is the exhaustion stage, in which the body's resources are depleted and resistance to stress is lowest. Therefore, the correct answer is C, exhaustion.