Consider a stack 𝑆 and a queue 𝑄. Both of them are initially empty and have…

Consider a stack 𝑆 and a queue 𝑄. Both of them are initially empty and have the capacity to store ten elements each. The elements 1, 2, 3, 4, and 5 arrive one by one, in that order. When an element arrives, it is assigned either to 𝑆 (pushed on 𝑆 ) or to 𝑄 (enqueued to 𝑄). Once all the five elements are stored, the output is generated in two steps. First, stack S is emptied by popping all elements. Then queue 𝑄 is emptied by dequeueing all elements. The output obtained by following this process is 4 3 1 2 5 .

Given the output, the objective is to predict whether an element was assigned to 𝑆 or 𝑄.
Which of the following options is/are possible valid assignment(s) of the elements?

Note: In the options, the notation 𝑥𝑆 denotes that element 𝑥 was assigned to 𝑆 and 𝑦𝑄 denotes that element 𝑦 was assigned to 𝑄.