Choose the word or phrase that best fits the blank space in the following passage.
By 1984, nonrenewable fossil fuels, such as oil, coal and natural as, provided over 82 percent of the commercial and industrial energy (26) ______ in the world. Small amounts of energy were (27) ______ from nuclear fission, and the remaining 16 percent came from burning direct perpetual and renewable fuels, (28) ______ biomass. Between 1700 and 1986 a large number of countries shifted from the use of energy from local sources to a centralized generation of hydropower and solar energy converted to electricity. The energy derived from nonrenewable fossil fuels has been (29) ______ produced in one location and transported to another, as is the case with most automobile fuels. In countries with private, rather than public (30) ______, the age of nonrenewable fuels has created a dependency on a finite resource that will have to be replaced.
(29)
A.actually
B.increasingly
C.gradually
D.consequently