C$25/$S$420,$ fyd $/$fcd$/$fctd $=365/17/1\mathrm{.}2$ MPa

a$)$ Find the maximum axial load it can carry $($for Md$=0)$

b$)$ Find the balanced axial load and the corresponding moment $($Nb$,$ Mb$)$

c$)$ Find the carrying capacity moment for Nd$=3600$ kN$.$

If the absolute error rate is less than $2\%,$ the solution can be accepted as correct.