In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Nephrons are the structural and functional units of the kidneys., Fact2: Mammalian kidneys form urine in nephrons., Question: Where do mammals make urine? (A) Kidneys (B) liver (C) alveoli (D) bladder (E) liquid (F) organ (G) toilets (H) sweating
A