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: freezing means changing from a liquid into a solid by reducing heat energy, Fact2: Solid ice is melted into liquid water., Question: How does water turn to ice? (A) Adding air (B) The bending of a ray of light (C) Warm air moving into cold air (D) Increasing heat energy (E) It used to be covered by water (F) evaporation (G) Adding salt (H) Reducing heat energy
H