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: Which of the following is the BEST example of something that causes a *** *** in the earth's surface?  (A) rainbows (B) floods (C) global warming (D) glacier.
[EX A]: E.

[EX Q]: Question: In humans, the digestion process begins in  (A) the intestine, with squeezing. (B) the mouth, with chewing and saliva. (C) the stomach, with churning and acid. (D) the esophagus, with pushing towards the stomach.
[EX A]: B.

[EX Q]: Question: *** purchased a *** for making a *** ramp. Which of the following is most *** to have for *** the *** ***?  (A) a picture showing the colors of different ramp parts (B) a diagram showing some ways to use the ramp (C) a list of prices for other available kits (D) a set of instructions for the kit material.
[EX A]:
E.