During his stay in Canada, he had quite a few frustrating experiences.

Answer: Option A

Disappointing : failing to fulfil someone's hopes or expectations.
Enthusiasm : intense and eager enjoyment, interest, or approval.
Humiliating : making someone feel ashamed and foolish by injuring their dignity and pride.
Repulsive : arousing intense distaste or disgust.
Frustrating : causing annoyance or upset because of an inability to change or achieve something.

Synonym of Frustrating is Disappointing