US lawmakers asked Apple Inc to explain the abrupt end of the political comedian Jon Stewart’s television show on its streaming service, according to a letter made public on Wednesday, citing concerns that content related to China was behind the cancellation. The New York Times reported last month that Stewart’s show on Apple’s streaming service was ending, the result of creative differences. The newspaper said Stewart told members of his staff that potential show topics related to China and artificial intelligence were causing concern to Apple executives. Apple declined comment…