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'.

Example Input: Question: New engine *** has helped cars get more *** per gallon of gas. Since gasoline comes from oil, this *** will affect the world *** of oil by  (A) increasing the need to search for more oil. (B) reducing the time it takes for oil to be renewed. (C) decreasing the amount of oil that exists underground. (D) extending the time that oil will be available for people to use.
Example Output: D.

Example Input: Question: *** *** *** primary energy source *** drives all weather events*** including precipitation*** *** *** tornados?  (A) the Sun (B) the Moon (C) Earth's gravity (D) Earth's rotatio.
Example Output: A.

Example Input: Question: When a guitar string is plucked, sound is produced by  (A) the size of the guitar. (B) the metal on the guitar. (C) the wood on the guitar. (D) the vibrations of the string.
Example Output:
D.