The correct answer is C. (general adaptation syndrome). According to Hans Selye, general adaptation syndrome has three phases. The first phase is called alarm; in this phase our sympathetic nervous system activates and our bodies mobilize to fight or flight. In the second phase, called resistance, we are completely supplied to deal with the situation. Finally, if the stressful situation is not resolved, we reach exhaustion phase. We cannot be fully engaged for unlimited amount of time.