The closest antonym for the word severe is minor.
Answer: Option D.
Explanation:
Antonym means a word which gives an opposite meaning to another word. For example the antonym for the word ‘good’ is ‘bad.’ In the sentence, ‘They might use it to cover large wounds or to treat people with severe burns’ severe means very bad or serious. So if we have to pick an antonym for the word severe, then it would most certainly be ‘minor’ which means slight or not quite severe. So if we replace severe with its antonym, then it would be ‘minor burns.’