Instructions: 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: Sponges have specialized cells called collar cells., Fact2: Flagellum of collar cell cause current to pass over collar and food is collected., Question: Which aspect of a sponge's cells allow it to collect food? (A) the cervix (B) teeth (C) flagellum (D) cartilage (E) plasma (F) osculum (G) tissue (H) potassium
Output:
C