【单选题】
直角弯角的计算公式()。
A、L=A+B-2*(R1+d)+π/2*(R1+d)/2
B、L=A+B-2*(R1+d)-π/2*(R1+d)/2
C、L=A+B+2*(R1+d)+π/2*(R1+d)/2
D、L=A-B-2*(R1+d)+π/2*(R1+d)/2
A、L=A+B-2*(R1+d)+π/2*(R1+d)/2
B、L=A+B-2*(R1+d)-π/2*(R1+d)/2
C、L=A+B+2*(R1+d)+π/2*(R1+d)/2
D、L=A-B-2*(R1+d)+π/2*(R1+d)/2