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").
Q: Fact1: gills are used for breathing water by aquatic animals, Fact2: Shark exhibit Come face to face with the ultimate aquatic predator., Question: What are gills used for breathing by sharks? (A) air (B) mussels (C) carbon monoxide (D) lava (E) fish (F) open (G) water (H) squids
A:
G