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 *** *** to *** a *** *** *** that will *** the same *** of *** *** *** it is ***. Which should the *** do *** when *** the *** tube?  (A) make a data table of amounts of toothpaste (B) gather building materials (C) create models of old toothpaste tubes (D) draw a few possible solution.
Example Output: E.

Example Input: Question: *** *** *** change *** chemical compositon *** iron?  (A) cause it to rust (B) cause it to melt (C) cut it into pieces (D) expose it to a magne.
Example Output: A.

Example Input: Question: *** species *** competes *** species B*** *** species *** *** stronger*** *** will *** likely happen *** species B?  (A) It will continue to live with species (A) (B) It will join with another species to compete with species (A) (C) It will move to another area away from species (A) (D) It will keep competing until species A is extinct.
Example Output:
E.