Generate a question which can yield the answer mentioned in the input. Generated question must be answered by the answer provided in input, without using any extra knowledge.

Q: Context : An order to enter the BTR-60P into Soviet Army service was issued on 13 December 1959. 
Answer : 13 December 1959

A: What year did BTR-60 come into use?
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Q: Context : The Boeing KC-767 is a military aerial refueling and strategic transport aircraft developed from the Boeing 767-200ER. 
Answer : Boeing 767-200ER

A: The Boeing KC-767 is based upon what?
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Q: Context : Rear Admiral Thorvald A. Solberg (17 February 1894 -- 16 May 1964) was a senior officer in the United States Navy, and the Chief of the Office of Naval Research from 1948 to 1951. 
Answer : United States Navy

A:
Which military branch is Thorvald A. Solberg a part of?
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