GATE | CSE 2023 | Question 41

Consider the pushdown automaton (PDA) P below, which runs on the input alpha-bet {a, b},  has  stack alphabet  {⊥, A},  and  has three states  {s, p, q},  with s  being the start state.  A transition from state u to state v, labelled c/X/γ, where c is an input symbol or ϵ, X is a stack symbol, and γ is a string of stack symbols, represents the fact that in-state u, the PDA can read c from the input, with X on the top of its stack, pop X from the stack, push in the string γ on the stack, and go to state v. In the initial configuration, the stack has only the symbol ⊥ in it. The PDA accepts by the empty stack.

Which one of the following options correctly describes the language accepted by P ?

(A)

(B)

(C)

(D)