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: Owen tested a physical property of a mineral. He rubbed a mineral sample on a piece of white tile. The mineral left a red mark on the tile. Which of the following physical properties of the mineral was Owen most likely testing?  (A) cleavage (B) hardness (C) luster (D) strea.
Example Output: B.

Example Input: Question: Which material is the best natural resource to use for making water-resistant shoes?  (A) cotton (B) leather (C) plastic (D) woo.
Example Output: B.

Example Input: Question: To *** conduct an *** using ***, what should students always do?  (A) Work in large groups. (B) Wear safety goggles. (C) Wear short sleeves. (D) Keep a window open.
Example Output:
E.