MANCHESTER, N.H. (Reuters) - Democratic U.S. Senator Bernie Sanders and former Indiana Mayor Pete Buttigieg exchanged barbs on Sunday in New Hampshire, two days before the state’s voters weigh in on who should win the right to take on Republican President Donald Trump in November. FILE PHOTO: Democratic U.S. presidential candidate Senator Bernie Sanders arrives to speak to canvassers and campaign volunteers in Concord, New Hampshire, U.S., February 8, 2020.