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").
Example: Fact1: a plant requires sunlight to grow, Fact2: Plants to avoid are fast-growing vines that can take over an area in no time., Question: What requires sunlight in order to take over an area? (A) spores (B) fish (C) plants (D) humans (E) pods (F) Oak (G) opossums (H) coral
Example solution: C
Example explanation: This is a good example. Based on the facts plants require sunlight in order to take over an area.

Problem: Fact1: an organism requires energy for growth, Fact2: Different organisms have different growth requirements and growth rates., Question: What is a requirement whose amount varies between organisms? (A) food (B) energy (C) existence (D) entropy (E) sunlight (F) H20 (G) entity (H) Energy.

Solution: B