已知一个栈的进栈序列是ABC，出栈序列是CBA，经过的栈操作是 。A:push,pop,push,pop,push,pop B:push,push,push,pop,pop,pop C:push,push,pop,pop,push,pop D:push,pop,push,push,pop,pop 答案: push,push,push,pop,pop,pop