The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, -890.3 kJ mol-1, -393.5 kJ mol-1 and -285.8 kJ mol-1 respectively. Enthalpy of formation of CH4 (g) will be
(a) -74.8 kJ mol-1
(b) -52.27 kJ mol-1
(c) +74.8 kJ mol-1
(d) +52.26 kJ mol-1