A.1.07 B.1.10 C.1.13 D.1.15
A.fcu.0≥fcu.k+1.645α B.fcu.0=fcu.k+0.645α C.fcu.0=fcu.k+1.1α D.fcu.0=fcu.k+2α
A.23.0% B.25.5% C.22.0% D.20.0%