instruction:
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'.
question:
Question: Electromagnets are used in many electric motors, generators, and simple devices. *** are much more useful than permanent magnets because unlike permanent magnets, electromagnets __________.  (A) come in a variety of sizes (B) have an attractive force (C) have two magnetic poles (D) can be turned on or of.
answer:
D.


question:
Question: A student is looking at insects using a *** ***. What about the insects can best be seen with the *** ***?  (A) different colors of insect bodies (B) how insects protect themselves (C) type of eyes insects have (D) size of the insect.
answer:
E.


question:
Question: Which of the following *** *** be *** into *** ***?  (A) nitrogen (B) zinc (C) air (D) aluminu.
answer:

E.