Detailed 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").
Problem:Fact1: Active immunity results when an immune response to a pathogen produces memory cells., Fact2: Vaccination is Active Acquired Immunity., Question: What results when an immune response to a pathogen produces memory cells? (A) anemia (B) vaccination (C) kill them (D) competition (E) lie detectors (F) rapid expansion (G) killing insects (H) it needs them
Solution:
B