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: Animals eat plants or other animals. How much and what they eat affects other parts of the ecosystem. These *** between the *** *** in an *** is called ___.  (A) interdependence (B) decomposition (C) environment (D) food webbin.
Example Output: A.

Example Input: Question: Which of the following would result in a decrease in the polar bear population in the arctic?  (A) An increase in the amount of grass (B) An increase in the fish population (C) A decrease in the fish population (D) A decrease in the human populatio.
Example Output: C.

Example Input: Question: Electricity to play your radio can be made using *** or nonrenewable resources. Which of the following *** are renewable?  (A) wind and oil (B) wind and sunlight (C) natural gas and oil (D) natural gas and coa.
Example Output:
B.