The correct option is D finale
Onset means the beginning of something, especially something unpleasant. The opposite of onset is finale, or the last part of a piece of music, an entertainment, or a public event, especially when particularly dramatic or exciting. Hence, Option C is correct. Among the rest of the options, hindrance means a thing that provides resistance, delay, or obstruction to something or someone, commencement means the beginning of something, middle means the point or position at an equal distance from the sides, edges, or ends of something.These do not express this antonym, hence incorrect.