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Classify the relation of question with context to one of these categories: 1) award received, 2) based on, collection, 3) conflict, 4) constellation, 5) convicted of, 6) date of death, 7) director, 8) drafted by, 9) educated at, 10) medical condition, 11) military branch, 12) narrative location, 13) occupation, 14) original network, 15) parent company, 16) point in time, 17) production company, 18) residence, 19) series, 20) service entry, 21) sex or gender, 22) spouse, 23) standards body question.

Context : Isaac Nicola Romero (1916 in Havana, Cuba -- 1997) was a prominent Cuban guitarist and one of the founders of the modern Cuban Guitar School. 
Question : What was Isaac Nicola's city of birth?
Solution: place of birth
Why? The question is about the place of birth of the Isaac Nicola. Hence the output is relevant and valid

New input: Context : Stockpiles of Mark 10 Mod 3 torpedoes were used extensively during the first part of World War II due to short supply of the newer and longer (246 in (6.2 m) Mark 14s, with some fleet submarines carrying a mixture of both types on patrol. Mark 10 torpedoes, and those developed at the same time (Mark 9 air- and Mark 8 surface ship-launched) used essentially the same control package (the Ulan gear) as the newer Mark 14 for depth and direction. The running depth could be set to between 5 and 35 m (16 and 115 ft). The gyro angle could be set for a new course up to 90 degrees port or starboard from the current course of the submarine before launch. The Mark 10 would run out of the tube straight ahead for the ``reach'', then turn to a new, pre-set course, through a total angular targeting of 180 degrees over the end of the submarine, and then run on this intercept course straight to the target. To use a Mark 10 Mod 3 (the earlier Mark 10 torpedo mod numbers would not work)) of torpedo in fleet submarine tubes required a gyro angle setting spindle adapter be slipped into the torpedo housing to extend the reach of the spindle into the torpedo. 
Question : In what year did Mark 10 torpedo enter service?
Solution:
service entry