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: Scientists observed several different organisms in the same forest environment. Which of the following organisms in this forest environment depend on dead plant and animal material for food?  (A) cockroach (B) tree (C) snake (D) robi.
Example Output: A.

Example Input: Question: A *** is *** the *** between a *** *** and a *** organism. Which *** is a *** of a *** organism?  (A) a student passing out water to a group (B) a student getting cereal from the cabinet (C) two students collecting trash from a group (D) four students working together to move a des.
Example Output: E.

Example Input: Question: *** system *** *** *** *** rid *** chemical waste *** water?  (A) digestive (B) urinary (C) locomotion (D) circulator.
Example Output:
B.