The 111 Power Plants Singled Out Under the George H

The 111 power plants singled out under the George H. W. Bush administration's 1990 compromise acid rain regulations were required to do which of the following?

A) Install smokestack scrubbers to lower their sulfur emissions
B) Burn low-sulfur coal to lower their sulfur emissions
C) Both install smokestack scrubbers and burn low-sulfur coal to lower their sulfur emissions
D) Do whatever was required to lower their sulfur emissions
E) Install small smokestacks with pivoting caps