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 Input: Question: Approximately how long does Earth take to complete its orbit around the Sun?  (A) one day (B) one month (C) one year (D) one centur?
Example Output: C.

Example Input: Question: What are the bundles of chemicals in our body called that control what we look like?  (A) cells (B) genes (C) DNA (D) filament?
Example Output: B.

Example Input: Question: The protective spines on a cactus are an example of  (A) adaptation (B) dispersal (C) photosynthesis (D) reproductio?
Example Output:
A.