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: Echinoderms lack respiratory and excretory systems., Fact2: Lung mechanics and gas exchange are topics during study of the respiratory system., Question: What do Echinoderms lack? (A) Lungs (B) Mass (C) oxygen (D) eardrum (E) gills (F) ovaries (G) Organs (H) Bodies
Output:
A