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: Plants use cellulose for their cell walls., Fact2: Basically, fiber is cellulose ., Question: Plants use what for their cell walls? (A) sugar (B) cations (C) sulfur (D) fiber (E) glucose (F) Carbon (G) Cane. (H) peat
D