An oxymoron is a term used to indicate a phrase that contains conflicting ideas.
A copy is a duplicate of the original. Therefore, 'a original copy' is an oxymoron as the original cannot be a copy. 'Crowd' means a large gathering. Therefore, 'a small crowd' is an oxymoron. A secret is something that is supposed to be known by others. Therefore, 'open secret' is an oxymoron as well.
All the given options are oxymorons. Therefore, option D is the right answer.
For the following questions answer them individually
Let us analyze what the author intends to convey through the given sentence.
'Although these injuries are not fatal,......'. The author acknowledges that the injuries are not fatal. By using the word 'although', the author conveys that he expects something to be done but that is not the case. The part that completes the sentence should capture this point.
'they are not ranked among top causes of death'. Had the option been 'they are ranked ...', we could have used this option to fill the blank. The given option cannot be used since it contradicts the term 'although' used in the first part of the sentence.
'they do not get reported'. There is nothing peculiar about minor injuries going unreported. This option will also make the usage of although in the first part of the sentence incorrect and hence, option D can be eliminated as well.
'there is no proof of the same'. This statement can be used to fill the blank. Let us check the other option and choose the most appropriate one between the two.
'they are certainly incapacitating and tragic'. This option aptly concludes by continuing the chain of thought. Though the injuries are not life threatening, they are certainly crippling. Therefore, option B is deemed better than option C and hence, option C is the right answer.
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.
'Blasphemous' means to commit something sacrilegious (against the religion or God). Ascetic means to renounce worldly pleasures and live as a hermit. Reverent means to hold something (God or elders) in high regard. Blarney is a term used to describe flattery.
'Reverent' is the term opposite in meaning to 'blasphemous'. Therefore, option B is the right answer.