SITUATION: An axially loaded rectangular tied column is to be designed for the following service loads

$DL=1600kN$

$LL=845kN$

Required Strength, $U=1\mathrm{.}2D+1\mathrm{.}6L$

Capacity Reduction Factor, $\frac{O}{?}=0\mathrm{.}65$

Effective cover to centroid of steel reinforcement $=70mm$

Concrete, $f{c}^{\text{'}}=27\mathrm{.}5$MPa

Steel, fy $=415$MPa

Using $3\%$ vertical steel ratio, what is the required column width $(mm)$ if the architectural conditions limit the width of the column in one direction to $350$ mm $?$

A$.500$

$450$

$550$

$400$