1968细节题。根据“Robert was murdered in 1968…”可知正确答案。

The story of the Kennedy brothers is rather like one of those songs which children sing happily and which end up with the shout, "and then there none."
     The eldest brother was killed in the war, John was shot in Dallas in 1963, Robert was murdered in 1968, and Edward’s chances of becoming president may have died when his ear had an accident, killing the passenger.
     The four boys were brought up by their father to do and fight for nothing but the best, whether on the games field, or in political life. He managed to give them so much ambition and energy that only the youngest brother found his political death, have people begun to ask themselves, "Why did we look on the Kennedys as the family chosen to lead the USA to a better future?"
     In fact, John and Robert had both shown their ability and courage in international politics and their work for civil rights, and Edward had a good record as senator; but so had many other people. Only history will show how much of the Kennedy story was built on fact and how much on the famous family name.