GMAT Sentence Correction (SC) | Re: Executives and federal officials say that the use of crack

119. Executives and federal officials say that the use of crack and cocaine is growing rapidly among workers,
significantly compounding the effects of drug and alcohol abuse, which already are a cost to business of
more than $100 billion a year.

(A) significantly compounding the effects of drug and alcohol abuse, which already are a cost to businessof
(B) significantly compounding the effects of drug and alcohol abuse, which already cost business
(C) significantly compounding the effects of drug
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