Given the task definition and input, reply with output. 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: the gravitational pull of the Moon on Earth 's oceans causes the tides, Fact2: Planetary moons are natural satellites., Question: The pull of what on the Earth's oceans cause the tides? (A) A yellow star (B) Time and energy (C) energy of moving objects (D) A natural satellite (E) flow of electrons (F) An artificial satellite (G) A red star (H) hydrogen and oxygen
D