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: a planet rotating causes cycles of day and night on that planet, Fact2: Rotation determines day and night, and the length of the day., Question: What causes night on a planet? (A) clouds (B) speed (C) Winter (D) rotation (E) Solar energy (F) axis (G) heat energy (H) wind
A:
D