The optimal solution of this linear programming problem is at the intersection of constraints $1(c_1)$ and $2(c_2).$

Max$2x_1+x_2$

s$.$t$.4x_1+1x_{2}400$

$4x_1+3x_{2}600$

$1x_1+2x_{2}300$

$x_1,x_{2}0$

Over what range can the coefficient of $x_1$ vary before the current solution is no longer optimal?

$1\mathrm{.}33c_{1}4$

$1\mathrm{.}45c_{1}4\mathrm{.}58$

$3c_{1}5$

$0\mathrm{.}5c_{1}1\mathrm{.}5$