Detailed Instructions: 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").
Q: Fact1: if a planet becomes too hot then that planet cannot sustain life, Fact2: Global warming linked to human emissions of heat-trapping gases is changing the planet's climate., Question: Global warming most threatens the Earth's ability to do what? (A) Sustain life (B) reproduce (C) Melt polar ice caps (D) growth (E) protect them (F) Resist erosion (G) to move people (H) Produce fossil fuels
A:
A