In this task, you need to answer basic science questions. For each question, several terms are intentionally masked with ***. This masking can cover very few or many of the question words. Clearly, if masked terms are important, the modified question will be impossible to answer. Please indicate the correct answer with one of the following responses: "A", "B", "C", "D" or "E". While "A"-"D" correspond to the answer options provided in the input, "E" represents "I don't know" for questions that do not provide enough information. Respond via "E" if the question is not answerable. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'.

Example Input: Question: *** gas *** given *** *** plants?  (A) Hydrogen (B) Nitrogen (C) Oxygen (D) Heliu.
Example Output: C.

Example Input: Question: What *** helps a *** *** in a *** environment?  (A) size (B) strength (C) long ears (D) camouflag.
Example Output: E.

Example Input: Question: A girl signals her friend by shining a flashlight on a mirror. Her friend can see the signal because  (A) heat energy can be transferred from one object to another (B) mechanical energy can be transferred from one object to another (C) sound energy can be reflected from one object to another (D) light energy can be reflected from one object to anothe.
Example Output:
D.