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").
Example: Fact1: a plant requires sunlight to grow, Fact2: Plants to avoid are fast-growing vines that can take over an area in no time., Question: What requires sunlight in order to take over an area? (A) spores (B) fish (C) plants (D) humans (E) pods (F) Oak (G) opossums (H) coral
Example solution: C
Example explanation: This is a good example. Based on the facts plants require sunlight in order to take over an area.

Problem: Fact1: gills are used for breathing water by aquatic animals, Fact2: Crustaceans are predominantly aquatic, breathing by means of gills., Question: Crustaceans breathe what through their gills? (A) matter (B) water (C) saliva (D) gametes (E) semen (F) liquid (G) oxygen (H) air

Solution: B