The correct answer is C. Dull.
An antonym is a word that means the opposite of another word. In this case, the word “acute” means sharp, severe, or intense. The word “dull” means not sharp, not severe, or not intense. Therefore, the word “dull” is the antonym of the word “acute.”
The word “sharp” means having a thin, pointed edge or point. For example, a knife is sharp.
The word “severe” means very serious or severe. For example, a severe storm is a very strong storm.
The word “intense” means very strong or powerful. For example, an intense pain is a very strong pain.
The word “dull” means not sharp, not severe, or not intense. For example, a dull knife is not a sharp knife. A dull pain is not a strong pain.