Hi
can anyone help me with this problem? I have looked around and cannot figure out why I keep getting the wrong answer.

Here is the problem..."Today there are more than four hundred potters around, all of who/whom make their pots by hand, following the traditions of the Paquime Indians.

The correct answer is Whom but I cannot figure out why. I
Can anyone help me?

Thank you!

Thomas

The problem lies in the use of "all of". Usually the trick to know whether to use who/whom is to use another pronoun. If the sentence was just "Today there are more than four hundred potters around, who make their pots by hand", "who" would be correct because it's "they make their pots by hand".

But in your example, it would sound strange: "all of they make their pots by hand". Instead it's "all of them make their pots by hand". Now why is it so? Because "all of them" is the subject here and not just what follows "all of".

awesome
thank you so much for the reply!

Simply because it is 'all OF whom'.

The most basic grammar is that prepositions take pronouns in the OBJECTIVE CASE - (nouns too, but there is no change in a noun between nominative and objective case.)
'who' is the nominative case form, and 'whom' is the objective case form.

Hence:
"Resume your ranks and legislative duties,
And take my daughters, all OF WHOM are beauties."
G&S: Pirates of Penzance.