Who和whom的用法解題

國三的小外甥參考書上的問題,請文法高手幫忙解惑,謝謝!
Listen to those people( )you believe are honest.
(A)who
(B)whom
(C)whose
(D)what
麻煩選出答案並且解釋為什麼,先感謝您的熱心解答!
3 answers 3