Definition: 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").
Input: Fact1: bacteria in soil convert atmospheric nitrogen into a form usable by plants, Fact2: More bacteria mean healthier soil., Question: What allows soil to convert atmospheric nitrogen into a usable form by plants? (A) hydrogen and oxygen (B) diseased soil (C) peachleaf willow (D) bacteria-free soil (E) healthier soil (F) nutrients (G) virus filled soil (H) Cooking
Output:
E