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 mold spore has a negative impact on the respiratory system, Fact2: Another name for the breathing tree is the respiratory system., Question: What do mold spores make it hard to do? (A) clean house (B) motility (C) kill them (D) breathe (E) reproduce (F) eat bread (G) play outside (H) survive
D