The angle between the rhumb line track and the great circle track is conversion angle which is half convergency.

Convergency = 14º so conversion angle =7º: great circle track = 270º + 7º = 277º

Remember the question is asking for the great circle track on arrival at B. The rhumb line track is 270ºT so great circle = 270º + conversion angle = 270º + 7º = 277ºT. The great circle track at A is 270º - 7º = 263ºT and the great circle track between A and B will change by 14º (convergency).