Which of the following has the largest amount of energy?

To determine which option has the largest amount of energy, it's essential to understand the energy content associated with each fuel type on a common basis.

1 gallon of #2 fuel oil contains approximately 140,000 to 150,000 British thermal units (BTUs) of energy. This makes it a highly energy-dense fuel, which is often used for heating purposes.

In contrast, 1 therm of natural gas is equivalent to about 100,000 BTUs. While it is widely used for heating and cooking as well, its energy content is less than that of 1 gallon of #2 fuel oil.

1 kilowatt-hour of electricity provides around 3,412 BTUs of energy. This is significantly lower than both heating oil and natural gas, as electricity's conversion factors do not allow for as high of an energy content in a physical quantity like gallons or therms.

1 pound of propane has an energy value of approximately 21,500 BTUs. Although propane is a common and efficient fuel source, its energy content per pound does not exceed that of heating oil or even natural gas by volume or therm.

Thus, when comparing the total energy content of these options, 1 gallon of #2 fuel oil stands out