Q: 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: energy is used for heating a building by a heating system, Fact2: Radiators are used to heat the building, The energy source is oil., Question: What do radiators use to heat buildings? (A) coal (B) CFCs (C) Solar power (D) Oil (E) Oxygen (F) hot (G) Hydrogen (H) fuse
A:
D