If height of the first storey of a building is 3.2 m and riser is 13 cm, the number of treads required, is

If height of the first storey of a building is 3.2 m and riser is 13 c

1.	If height of the first storey of a building is 3.2 m and riser is 13 cm, the number of treads required, is
A.	12
B.	18
C.	24
D.	25
Answer» D. 25