<p>In the 1960s, Cesar Chavez organized migrant farmworkers, many of them Mexican Americans, into a labor union that supported nationwide boycotts of both lettuce and grapes. No error</p>
<p>I chose B think think that it should be something like "many of whom were Mexican Americans," but the answer is E. Could someone help explain when i need to use who/whom, and which one when?</p>
<p>Thanks in advance.</p>
<p>Yes, I agree this is a tricky one.</p>
<p>Is this from the BB?</p>
<p>The usage of who/whom is irrelevant to the question. “many of them” is correct because “them” is in the objective case; you need to use the objective case when there is a preposition preceding it. The object of preposition, which is "of
in this case, is “them”. E is the correct answer.</p>
<p>whom would work, but them works also. Perhaps whom would be slightly better wordchoice, but there is nothing wrong with “them”</p>
<p>the answer is E</p>