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: insulated material can be used for keeping warm, Fact2: An insulated cup with a cover is great for keeping beverages warm., Question: How do you keep a cup hot? (A) less water (B) electricity (C) heat energy (D) adding heat (E) energy usage (F) insulation (G) squeeze (H) energy
F

Fact1: vinegar can cause harm to the eyes, Fact2: Vinegar is dilute acetic acid., Question: What can acetic acid do to the eyes? (A) treat cataracts (B) harm them (C) Relieve pain (D) Dehydration (E) kill them (F) hydrate them (G) protect them (H) cleanse them
B

Fact1: Antigens are molecules that the immune system recognizes as foreign to the body., Fact2: Antibodies are produced to fight antigens., Question: What happens when the immune system recognizes a foreign substance? (A) an area swollen with pus (B) The immune system fails (C) irradiation (D) Bacteria dies (E) Antibodies are formed (F) major threat to health (G) Something that causes allergies (H) Viruses reproduce
E