Please explain the approach to solve the problem and point to any relevant material available in the GMAT club.
My answer is (E).
- take away (A) and (B): the underlined phrase is a modifier for cows so we need a modifier in passive voice because cows cannot provide and milk themselves.
- take away (c): unparallel as "provided" v.s "milking"
- Left (d) and (e): eliminate (d) because
--> "the": we are talking about a kind of cows Holstein, we dont mean the certain number of Holstein.
--> "cow": we need plural not singular as we have pronoun "them" to refer to "cows".
--> present future "will" might be better used present simple "produces" in this case
Hope my explanation helps in some ways.
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