Final answer:
The calorific value of propane in Btu per cubic foot is within the range of 2500-3000 Btu/cu ft, which corresponds to option C.
Step-by-step explanation:
The calorific value of propane in British Thermal Units (Btu) per cubic foot can be found in option C) 2500-3000 Btu/cu ft. Propane is a hydrocarbon fuel and a valuable energy source; its calorific value measures the amount of heat energy released during its combustion. The information provided indicates that one gallon of liquid propane contains approximately 91,500 Btu, which translates to 0.915 Therms. Given that there are about 3.785 liters in a gallon, and the density of propane is mentioned as a factor, we can deduce that the calorific value of propane is quite high, accurately falling within the range given in option C.