GATE | CSE 2023 | Question 59

Consider a sequence a of elements a0 = 1, a1 = 5, a2 = 7, a3 = 8, a4 = 9, and a5 = 2. 

The following operations are performed on a stack S and a queue Q, both of which are initially empty.
I: push the elements of a from a0 to a5 in that order into S.
II: enqueue the elements of a from a0 to a5 in that order into Q. III: pop an element from S.
IV: dequeue an element from Q. V: pop an element from S.
VI: dequeue an element from Q.
VII: dequeue an element from Q and push the same element into S. VIII: Repeat operation VII three times.
IX: pop an element from S. X: pop an element from S.
The top element of S after executing the above operations is________

(A)

(B)

(C)

(D)