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: *** of any *** *** ___.  (A) when the particles of the substance are able to slide past one another (B) at 0Â°C (C) when a liquid changes to a solid, regardless of temperature (D) when energy is added to a substanc.
[EX A]: E.

[EX Q]: Question: *** system *** responsible *** getting rid *** chemical waste *** water?  (A) digestive (B) urinary (C) locomotion (D) circulator.
[EX A]: B.

[EX Q]: Question: Ella is raising *** in an aquarium. Which is the best *** for the amount of *** needed to fill a household *** that holds three fish?  (A) 25 milliliters (B) 25 centiliters (C) 25 liters (D) 25 kiloliter.
[EX A]:
C.