og12-67 a答案的解釋問題

Several industries have recently switched at least
partly from older technologies powered by fossil fuels
to new technologies powered by electricity. It is thus
evident that less fossil fuel is being used as a result of
the operations of these industries than would have
been used if these industries had retained their older
technologies.
Which of the following, if true, most strengthens the
argument above?
(A) Many of the industries that have switched at
least partly to the new technologies have
increased their output.
(B) Less fossil fuel was used to manufacture the
machinery employed in the new technologies
than was originally used to manufacture the
machinery employed in the older technologies.
(C) More electricity is used by those industries that
have switched at least partly to the new
technologies than by those industries that have
not switched.
(D) Some of the industries that have switched at
least partly to the new technologies still use
primarily technologies that are powered by
fossil fuels.
(E) The amount of fossil fuel used to generate
the electricity needed to power the new
technologies is less than the amount that would
have been used to power the older technologies

我选对了但是A答案的解释怎说A实际上在weaken呢?
(a) in an indirect way, this option slightly weakens rather than strengthens the argument. For if fossil fuls are used to produce the electricity now used by the inductries and if it is because of these newer tech that output has incresed, the argument's conclusion is less likely. 没明白为什么industries output increase了会weaken argument. 请赐教.....