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. I have taught hundreds of students,___________ having been working in their fields for years.

A.some of whom      B.some of them      C.most of whom     D.who

. I have taught hundreds of students,___________ having been working in their fields for years.

A.some of whom      B.some of them      C.most of whom     D.who

. I have taught hundreds of students,___________ having been working in their fields for years.