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: When an *** *** ***, it *** *** *** *** into the ***. The *** MOST *** *** the ***  (A) move quickly through the water. (B) breathe oxygen from the water. (C) hide from predators. (D) use food faster.
Example Output: E.

Example Input: Question: *** *** *** *** *** ****** ****** ****** *** *** *** *** *** ***  (A) records from history. (B) natural motions of the sun. (C) natural motions of the Earth. (D) natural motion of the moon.
Example Output: E.

Example Input: Question: A student is given three identically sized blocks. Each block is made of a different material. What characteristic of the blocks should be examined to find out which block is made of metal?  (A) color (B) weight (C) texture (D) conductivit.
Example Output:
D.