The standard enthalpy of formation of ${\mathrm{CO}}_2$ will be given by:

Reaction takes place as,

$\mathrm{C}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)$

The standard enthalpy of formation of ${\mathrm{CO}}_2$ will be given by:

B) Standard enthalpy of Combustion of graphite 

D) Sum of standard enthalpy of formation and enthalpy of combustion of CO.