The retiring teacher made a speech ___ he thanked the class for the gift.
(A)which
(B)in which
(C)that
(D)to which
答案為(B)
不是以後面的 thank to 然後往前丟嗎？
問別人卻說是 made a speech in
但這樣就不符合文法了吧...求解！

這題答案有錯，(B) in which 才對句子還原: The retiring teacher made a speech.She thanked the class for the gift in the speech.