Teacher: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").
Teacher: Now, understand the problem? Solve this instance: Fact1: Air pollution harms the respiratory and circulatory systems., Fact2: Incinerated mercury pollutes the air., Question: What harms the respiratory and circulatory systems? (A) Greenhouse gasses (B) burning coal (C) inoculation (D) incinerated mercury (E) fossil fuels (F) water vapor (G) Sulfur dioxide (H) air
Student:
D