多选题

There're 5 elements a,b,c,d,e to be p...

Question

There're 5 elements a,b,c,d,e to be pushed into a Stack in the alphabetical order, which one(s) below is(are) the possible pop up sequence?

A. a,b,c,d,e

B. e,d,c,b,a

C. c,b,d,a,e

D. c,a,b,d,e