The thickness of the topg of a ribbed slab, varies between________________?
A. 3 cm to 5 cm
B. 5 cm to 8 cm
C. 8 cm to 10 cm
D. 12 cm to 15 cm
A. 3 cm to 5 cm
B. 5 cm to 8 cm
C. 8 cm to 10 cm
D. 12 cm to 15 cm