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").

[Q]: Fact1: a light bulb converts electrical energy into light energy when it is turned on, Fact2: Light bulbs are rated in Watts., Question: How is converted energy into light energy rated? (A) energy (B) unique (C) heat (D) good (E) watts (F) parsec (G) kilojoule (H) kinetic energy
[A]: E

[Q]: Fact1: Some viruses can cause cancer., Fact2: Cancer is an example of a mutation in cells., Question: What can mutate cells? (A) Allergies (B) water (C) fruits (D) flow of electrons (E) vegetables (F) harmful substances (G) rays or beams (H) some viruses
[A]: H

[Q]: Fact1: matter vibrating can cause sound, Fact2: All guitars produce sound through the mechanical vibration of strings., Question: What do guitar strings do? (A) Charge the guitar (B) Relieve pain (C) Vibrates (D) reproduce (E) squeeze (F) Bend (G) Create silence (H) Mute the guitar
[A]:
C