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: increasing heat causes thermal expansion, Fact2: An increase in temperature is the result of the flow of heat into the system., Question: he flow of heat into the system causes what? (A) thermal shields (B) thermal detonation (C) thermal expansion (D) Plant growth is reduced (E) chemical reaction (F) Evaporation (G) kinetic energy (H) thermal heat
C