—Why were you so late this morning?

—I _____ in heavy traffic for an hour on the way here.

A．have been caught

B．have caught

C．had caught

D．was caught

没有关键码序列(17，8，3，25，16，1，13，19，18，4，6，21) ，要按关键码值递增的次序排序，用初始增量为4的希尔排序法，一趟扫描后的结果是______。