Life in the villages is very dull.

Answer: Option D

Dull : lacking interest or excitement.
Serious : demanding or characterized by careful consideration or application.
Wasteful : (of a person, action, or process) using or expending something of value carelessly, extravagantly, or to no purpose.
Bluffing : try to deceive someone as to one's abilities or intentions.
Pleasant : giving a sense of happy satisfaction or enjoyment.

Antonym of Dull is Pleasant