You will be given a definition of a task first, then some input of the task.
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: Echinoderms lack a centralized nervous system., Fact2: Echinoderms include starfish, sea urchins, and sea cucumbers., Question: Starfish, sea urchins and sea cucumbers lack a what? (A) characteristics (B) the body's largest organ (C) watery habitat (D) centralized nervous system (E) functioning arm (F) underwater life (G) biological diversity (H) epidermis and dermis
Output:
D