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: *** *** *** *** *** *** ****** *** *** *** *** ***  (A) newspapers. (B) phonebooks. (C) paper towels. (D) soda cans.
Example Output: E.

Example Input: Question: The *** heard when a *** *** is *** is caused by  (A) vibration. (B) refraction. (C) momentum. (D) acceleration.
Example Output: A.

Example Input: Question: Which two senses would BEST help a person measure hair length?  (A) Taste and smell (B) Touch and sight (C) Sight and hearing (D) Smell and hearin.
Example Output:
B.