that
which
who
it
本题考查定语从句的引导词。which is quite unexpected为非限制性定语从句,修饰前文的we have raised 50,000 pounds for the poor children,故用which引导。故选B。
句意:到目前为止,我们已经为贫困的孩子筹到5000镑的钱,这是相当令人意外的。