单项选择题

A.ρ=ρmin/γ,ρmin=As/(b*h)
B.ρ=As/(b*h0),ρmin=max{0.2%,0.45*ft/fy}
C.ρ=max{0.2%,0.45*ft/fy};,ρmin=As/(b*h)
D.ρ=0.45*ft/fy,ρmin=0.2%