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: threatening behavior by predators causes a porcupine to extend its quills, Fact2: Puffers are smooth skinned while Porcupines have the characteristic spines or quills., Question: What does a porcupine do with its spines when it's threatened? (A) killing insects (B) Shoot them (C) kill them (D) protect them (E) Extend them (F) Shed them (G) Retract them (H) behave
[EX A]: E

[EX Q]: Fact1: soil is formed by rocks eroding, Fact2: Rivers erode the rocks they flow over., Question: What is formed by rivers? (A) fish (B) soil (C) rain (D) bamboo (E) spring (F) clouds (G) kayaks (H) NaCl
[EX A]: B

[EX Q]: Fact1: if a tree falls then sunlight becomes available to the surrounding plants, Fact2: Large pine trees also provide good shade., Question: what provides more sunlight to surrounding plants by falling? (A) small shrubs (B) grass (C) wind (D) light rays (E) LEDs (F) roots (G) pine (H) sugar
[EX A]:
G