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'.

[EX Q]: Question: Which is a *** of a *** that is most *** a *** of its ***?  (A) its color (B) its length of ears (C) its food preference (D) its ability to see in the dar.
[EX A]: E.

[EX Q]: Question: All *** *** on *** are *** *** or nonrenewable. Whether a *** is *** or *** *** on how *** or *** the *** is ***. If the *** is *** *** than it is ***, then the *** ***, in ***, ***. Which *** *** the *** of a *** *** resource?  (A) A group of people swims in a river. (B) A construction crew builds an iron bridge. (C) A farmer grows vegetables to sell at a local market. (D) A person bakes a cake with electricity produced by a hydroelectric power plant.
[EX A]: E.

[EX Q]: Question: When an *** *** *** in a *** *** is *** to a ***, it ***  (A) a battery. (B) an engine. (C) an insulator. (D) an electromagnet.
[EX A]:
E.