The most probable meaning of the word "opulence" (Line 9, Para. 1 )may be ______.

A．the turbine that powers the generator
B．the generator that produces electricity
C．the cylinders that drives the turbine
D．the air that escapes from the turbine

A．there is a severe shortage of coal and petroleum
B．it is the cheapest method of producing energy
C．petroleum supplies are being steadily drained
D．obtaining energy from ocean water are simpler