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: Passive immunity lasts only as long as the antibodies survive in body fluids., Fact2: Antibodies are administered to the patient in a process called passive immunization., Question: How long can antibodies protect the body? (A) As long as antibodies survive (B) Slowing the transfer of heat (C) For a set time (D) by keeping them warm (E) it protects them (F) Into elderly years (G) As long as the human survives (H) A compound that donates proton
Output:
A