TEXT C The earliest vertical
windmills were used in Persia more than 2,000 years ago for the grinding of
grain. Windmills were adopted for pumping water in North America by the middle
of the nineteenth century. Their use declined drastically in the 1930’s when
inexpensive electricity reached the rural areas. A renewed interest in the use
of wind power to generate electricity followed the energy crisis of the 1970’s.
A program of the United States Department of Energy encouraged the development
of new machines, the construction of wind farms, and an evaluation of the
economic effect of a large scale Use of wind power. Public
acceptance of wind energy conversion systems is an important consideration in
planning for the widespread application of wind energy. Studies have shown that
the environmental impact of such systems is relatively small compared with
conventional electric power systems. Wind-powered systems do not require the
flooding of large land areas or the alteration of the natural ecology, as
dohydroelectric systems. Furthermore; they produce no waste products or thermal
or chemical effluents, as fossil-fueled and nuclear fueled systems do. Which of the following most probably led to a decreased use of windmills in the U. S.
A．The advent of nuclear energy. B．Increased environmental awareness. C．The availability of inexpensive electricity in rural areas. D．A long-term shift in wind currents.