Given the task definition, example input & output, solve the new input case.
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).
Example: 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.
Output: D.
We know that the vibrations of the string produces sound in a guitar. So, the correct answer has to be "D".

New input case for you: Question: How are a tree and grass alike?  (A) Both make wood. (B) Both have roots. (C) Both need moonlight. (D) Both have short lives?
Output:
B.