Detailed Instructions: In this subtask, you will answer a simple science question. Please indicate the correct answer. If you're not sure about the answer, choose the last option "I don't know". Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. The "A"-"D" responses correspond to the answer options mentioned in the input. There is a 5th option "E" which should be used for questions for which you're not sure about the answer (e.g., when the questions do not provide enough information to answer).
See one example below:
Problem: Question: When a guitar string is plucked, sound is produced by  (A) the size of the guitar. (B) the metal on the guitar. (C) the wood on the guitar. (D) the vibrations of the string.
Solution: D.
Explanation: We know that the vibrations of the string produces sound in a guitar. So, the correct answer has to be "D".

Problem: Question: Which physical characteristic do some organisms have that helps them survive in the Arctic?  (A) growing tall to hide in trees (B) changing fur color to hide from predators (C) developing large paws to protect themselves from the wind (D) producing shallow root systems to protect themselves from the cold ai?
Solution:
B.