单项选择题

已知边长DMN=73.469m,方位角aMN=115°18′12″,则△xMN和△yMN分别为()

A.+31.401m,+66.420m
B.+31.401m,-66.420m
C.-31.401m,+66.420m
D.-66.420m,+31.401m