Today is the day your younger sister's first choice for college said she would get her acceptance (or rejection) letter in the mail. it's 3: 00 p. m. and the mail, which usually comes by noon, still hasn't been delivered. most likely your sister is experiencing

Frustration

Explanation:

Frustration: In psychology, the term frustration is referred to as a similar emotional response towards anger, irritation, disillusionment, annoyance, and outrage, etc. An individual encounters frustration when he or she experience resistance from fulfilling his or her goals or desires and it often increases if the desired goal is not being fulfilled, blocked, or denied.

Example: A person encounters frustration when he or she couldn't perform well in the examination and got a bad mark.