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: *** containers can be *** and made into new ***. How will *** *** most likely *** ***?  (A) People will use less energy. (B) People will drink more soda. (C) People will add less to landfills. (D) People will buy more things in cans.
Example Output: C.

Example Input: Question: Which example best shows *** that make up the *** *** in the *** ***?  (A) heart, blood, vessels (B) nose, trachea, lungs (C) brain, spinal cord, nerves (D) esophagus, stomach, intestine.
Example Output: E.

Example Input: Question: A student mixed salt and sugar. Which statement describes the physical properties of salt and sugar after they were mixed?  (A) The sugar dissolved the salt. (B) The salt and sugar changed color. (C) The sugar and the salt were unchanged. (D) The salt and sugar formed a new material.
Example Output:
C.