C. you are extremely nervous and start sweating while waiting in line for your name to be called to accept your high school diploma
Explanation:
Eustress is an advantageous stress because under this kind of stress, a person is spurred on or challenged to achieve a goal. At first the challenge makes him apprehensive, but the end result is beneficial or useful. For example, the stress a person feels before exercise is beneficial because when the challenge is faced headlong, the end-result is advantageous.
The stress described above is also beneficial because the end-result is likely an acceptance letter and that is good and favorable news.
