In the chemical reaction below, $500kJ$ of heat was released:

$2A_{(s)}+2B_{(1)}2C_{(s)}+D_{(1)}$

Determine the heat of formation at standard state in $k\frac{J}{m}ol$ of $C$ if:

$A_{(s)}=-150k\frac{J}{m}ol$

$B_{(I)}=-100k\frac{J}{m}ol$

$D_{(I)}=850k\frac{J}{m}ol$