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: Mollusks have a circulatory system with one or two hearts that pump blood., Fact2: Arthropods and most mollusks have an open circulatory system., Question: What kind of circulatory system do arthropods have? (A) open (B) toads (C) closed (D) porous (E) fluid (F) H 2 O (G) tissue (H) koalas
Output:
A