The Law Passed by Congress in 1977 to Deal with Acid

The law passed by Congress in 1977 to deal with acid rain called for

A) the burning of only low-sulfur coal in all new plants.
B) both scrubbers and the burning of low-sulfur coal in all new plants.
C) scrubbers in all new plants.
D) both scrubbers and the burning of low-sulfur coal in all plants, both new and existing.
E) use of small smokestacks with pivoting caps.