A. G17 G90 G03 X-30.0 Y0 R--50.0 F50 B. G18 G90 G03 X-30.0 Y0 R-50.0 F50 C. G17 G90 G02 X30.0 Y0 R-50.0 F50 D. G17 G90 G02 X-30.0 Y0 R50.0 F50
A. 正确 B. 错误