15. 下列 NC 程式何者正確 (A)G42 G01 X10.0 Y10.0 D01;G91 Z50.0; G90 Z20.0; (B)G90 G43 Z10.0 H01 S400 M03; (C)G90 G17 X0.0 Y0.0;G42 G01 D01 F100.; S2000; M08; (D)G42 G03 X10.0 Y10.0 R10.;