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: gravity causes objects that have mass to be pulled down on a planet, Fact2: Weight is the product of an object's mass and the acceleration due to gravity., Question: What does gravity's pull determine about an object? (A) speed (B) Joules (C) Energy. (D) Weight (E) size (F) density (G) toughness (H) energy
D