A. plenty
B. monotonous
C. unhappy
D. cheerful
Dreary : depressingly dull and bleak or repetitive.
Plenty : a large or sufficient amount or quantity; more than enough.
Monotonous : dull, tedious, and repetitious; lacking in variety and interest.
Unhappy : not happy.
Cheerful : noticeably happy and optimistic.
Antonym of Dreary is Cheerful
