Sum of tread and rise must lie between_______________?
A. 300 to 350 mm
B. 400 to 450 mm
C. 500 to 550 mm
D. 600 to 650 mm
A. 300 to 350 mm
B. 400 to 450 mm
C. 500 to 550 mm
D. 600 to 650 mm