Official Solution:The 1970 amendments to the Clean Air Act were sweeping, requiring that both federal monitoring of stationary as well as mobile emissions take place.A. requiring that both federal monitoring of stationary as well as mobile emissions take place.
B. requiring federal monitoring of both stationary and mobile emissions.
C. with the requirement of federal monitoring of both stationary and mobile emissions.
D. and they required the federal monitoring of both stationary and mobile emissions.
E. and they required that federal monitoring of stationary as well as mobile emissions take place.
(A) The word 'both' is in the wrong place; the sentence should read 'federal monitoring of both'. The phrase 'as well as' should be replaced by 'and'.
(B) Correct. 'Both' is placed correctly and the present participle 'requiring' is used correctly.
(C) 'with the requirement of' is awkward and wordy.
(D) This sentence introduces the unnecessary pronoun 'they'. The phrase 'the federal monitoring' is unnecessarily wordy; it could simply be expressed as federal monitoring.
(E) This sentence introduces the unnecessary pronoun 'they'; 'as well as' is used incorrectly.
Answer: B