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'.

[EX Q]: Question: Ice cream in a bowl changed from *** to *** in a few minutes. Which of the following most likely caused this change?  (A) Bacteria grew in the ice cream. (B) Heat was added to the ice cream. (C) Water evaporated from the ice cream. (D) Frozen berries were sprinkled on the ice cream.
[EX A]: B.

[EX Q]: Question: *** *** *** *** enables *** animal *** *** oxygen?  (A) Digestive System (B) Cirulatory System (C) Respiratory System (D) Nervous Syste.
[EX A]: C.

[EX Q]: Question: *** *** *** *** in a *** *** of *** and *** it. After he *** *** the bottle, he *** that *** *** of the *** were *** in the water. What is the best *** he *** *** *** on this ***? If *** the *** *** *** of *** to *** off, ___.  (A) then using cold water will break off more pieces (B) then using hot water will make the stones change colors (C) then shaking for a longer amount of time will break off more pieces (D) then shaking for a shorter amount of time will make the rocks change color.
[EX A]:
E.