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'.

[Q]: Question: Electromagnets are *** in many *** ***, ***, and *** ***. *** are *** more *** than *** *** *** *** *** magnets, *** __________.  (A) come in a variety of sizes (B) have an attractive force (C) have two magnetic poles (D) can be turned on or of.
[A]: E.


[Q]: Question: A company *** *** on a *** ***. Which of these is the BEST *** for *** the trees?  (A) The trees provide oxygen for the soil. (B) The trees prevent soil from washing away. (C) The trees make shade for animals living there. (D) The trees cause animals to move to other places.
[A]: E.


[Q]: Question: Which of the following items in a *** *** *** with the help of an ***?  (A) dump truck (B) crane to pick up, haul, and drop cars (C) fence that surrounds the wrecking yard (D) dumpster for leftover part.
[A]:
E.