(d)
Heat of combustion is usually measured by placing a known mass of a compound in a steel container called a constant volume bomb calorimeter.
$\mathrm{\Delta}E = C \times \mathrm{\Delta}t \times \frac{M}{m}$
Where, C=heat capacity of calorimeter, $\mathrm{\Delta}t = (t_{2} - t_{1})$ $m$=mass of substance taken and $M$=molar mass of substance