A slab of 150 mm gross depth is reinforced with 12 mm bars at a spacing of 14.4 cm (Primary reinforcement). Which among the following options can also be used as an alternative for reinforcing this slab? Effective cover = 20mm
1
8 mm bars at 6.4 cm spacing
2
10 mm bars at 10 cm spacing
3
16 mm bars at 25.6 cm spacing
4
20 mm bars at 40 cm spacing