高中英语选择,定语从句.
Bynineo'clock,alltheolympictorchbearershadreachedthetopofmountQomolangma,_____apearedararerainbowsoon.
a.ofwhichB.onwhichCfromwhichDabovewhich
此题从句不是缺主语吗?介词+which不是