Which form of transportation conserves the most nonrenewable resources?

Heavy vehicles that take many passengers in them would prove most efficient in fuel saving.

Pulling vehicles or taking buses or trains to travel  would mean that for the same amount of fuel that is needed for the vehicle to travel from one place to another it is carrying many passengers does the fuel consumption is divided among the passengers making it most reasonable and most efficient transportation to save fuel.  

i believe the answer would be:

d. violin, clarinet, french horn, and tuba