单项选择题

A.G85 X50.0 Y50.0 Z-10.0 R6 F60
B.G81 X50.0 Y50.0 Z-10.0 R-6 F60
C.G81 X50.0 Y50.0 Z-10.0 R3.0 F60
D.G83 X50.0 Y50.0 Z-10.0 R3.0 F60