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.
--------
Question: Context : William MacCormac was born in Belfast, Northern Ireland, the son of Dr Henry MacCormac, a notable Northern Irish physician, and his wife Mary MacCormac (née Newsam), the daughter of a prominent Anglo-Irish family. 
Question : The year William MacCormac died was what?

Answer: date of death


Question: Context : The Tiger II was under-powered, like many other heavy tanks of World War II, and consumed a lot of fuel, which was in short supply for the Germans. 
Question : In what year did Tiger II enter service?

Answer: service entry


Question: Context : Besides being a statesman, Johan de Witt also was an accomplished mathematician. 
Question : The year Johan de Witt died was what?

Answer:
date of death