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").

[EX Q]: Fact1: Carbon may be stored in sedimentary rock for millions of years., Fact2: Limestone is a type of sedimentary rock., Question: What element can be stored in limestone for millions of years? (A) oxygen (B) Energy (C) matter (D) carbon (E) sodium (F) helium (G) rock salt (H) heat
[EX A]: D

[EX Q]: Fact1: Ants communicate with chemicals called pheromones., Fact2: Ants are of extreme importance in the insect world., Question: How do some insects communicate? (A) sound (B) sensory neurons (C) Decibels (D) electronic waves (E) progesterone (F) Vibrates (G) pheromones (H) radio waves
[EX A]: G

[EX Q]: Fact1: Arthropods have a life cycle with sexual reproduction., Fact2: Insects are the largest group of arthropods., Question: What type of creatures have sexual reproduction as part of their life cycle? (A) plants (B) insects (C) proteins (D) ducks (E) animals (F) gametes (G) prions (H) fungi
[EX A]:
B