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 greenhouse is used to protect plants by keeping them warm, Fact2: Flowers are the major greenhouse crops., Question: what are the major crop that needs protecting by keeping them warm (A) our planet (B) organisms (C) Earthworms (D) Flowers (E) Echinoids (F) toughness (G) support (H) cellulose
A:
D