The 1960 sit-in at greensboro, north carolina: a. ended in a riot with ten injured. b. encountered a harsh reaction from greensboro's police force, which jailed the four ringleaders. c. did not end with integration of the woolworth's lunch counter. d. sparked similar successful demonstrations throughout the south. e. was staged in one of the most notoriously racist cities of the south, where angry residents remained deeply committed to the racial divide.