Which one of the following has the highest fuel value?

Hydrogen has the highest fuel value (approximately 141,800 kJ/kg) among the options listed. Fuel value refers to the heat energy released per unit mass of fuel. Hydrogen's high energy content per mass, combined with its clean combustion producing only water, makes it an ideal fuel in terms of energy density. Gasoline (~44,000 kJ/kg), natural gas (~50,000 kJ/kg), and charcoal (~30,000 kJ/kg) have significantly lower fuel values.