The word in the following pair have a certain relationship with each other. Given in the options are four pairs of related words. Select the pair with the same relationship as the given pair.

Cacophony:Euphony

Cacophony is a term used to describe a noisy condition. Euphony is a term used to describe sounds that are pleasing to the ears. Therefore, the given pair of words are antonyms. 

Belligerent is an adjective used to describe someone who is aggressive.
Serene is a term used to describe a calm situation. Mostly, belligerent is used as an attribute to describe a person and serene is used to describe a situation.

Loneliness and peace cannot be termed as antonyms. The same is the case with horrific and sympathetic.

Nocturnal is a term used to denote animals that are active at night. Diurnal is a term used to denote animals that are active during the day. Therefore, nocturnal and diurnal are antonyms and hence, option D is the right answer.