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: The *** of the *** in its *** around the *** is the Earth's ___.  (A) rotation (B) revolution (C) evolution (D) til.

Answer: E.


Question: Question: Electromagnets are used in many *** ***, ***, and simple devices. *** are much more *** than *** *** because unlike *** 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 vaccine can prevent a serious disease. When a new vaccine is developed, it is given to a small group of people. Why would it be important to *** each vaccine on a small group of people before everyone can have one?  (A) to figure out how much the vaccine is worth (B) to determine how the vaccine will affect people (C) to understand how that disease affects the human body (D) to find out how many people are affected by the diseas.

Answer:
B.