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: Roundworms may be free-living or parasitic., Fact2: Roundworms make up the roundworm phylum, Nematoda., Question: What can the phylum Nematoda be? (A) dangerous (B) parasitic (C) horses (D) meiosis (E) more abundant (F) graptolites (G) homogenous (H) phytoplankton
Output:
B