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: *** *** rain *** *** ***  (A) energy. (B) evaporation. (C) precipitation. (D) clouds.
Example Output: E.

Example Input: Question: *** *** *** has *** *** get more *** *** *** of ***. Since ***oline *** from oil, this *** *** *** the *** *** of *** by  (A) increasing the need to search for more oil. (B) reducing the time it takes for oil to be renewed. (C) decreasing the amount of oil that exists underground. (D) extending the time that oil will be available for people to use.
Example Output: E.

Example Input: Question: *** serve important *** in an ecosystem. One of the things they do is ___.  (A) reduce nutrients in the soil (B) reduce insect populations (C) recycle nutrients (D) recycle wate.
Example Output:
E.