C
Plastic has been replacing aluminum in a widening array of military equipment because it offers equal protection at less weight. A plastic-armored vehicle is, however, twice as costly to make as an aluminum-armored vehicle. Ttherefore, the replacement of aluminum-armored vehicles by plastic-armored vehicles that offer equal protection is not yet advisable from a financial point of view. Which of the following, if true, casts most doubt on the conclusion above?
A: Although the cost of plastic is expected to remain stable, the growing practice of recycling metals will probably drive down the cost of metals.
B: The cost of repairing body damage on plastic-armored vehicles would exceed what the military currently spends to repair body damage on aluminum-armored vehicles.
C: A plastic-armored vehicle could be operated at one-third the current cost of operating an aluminum-armored vehicle.
D: The aluminum-armored vehicle is the least costly to maintain of all the metal-armored vehicles currently used by the military.