#include &lt;iostream&gt;    #include &lt;queue&gt;      using namespace std;    int main &#40;&#41;    &#123;        queue&lt;int&gt; myqueue;        myqueue.push&#40;12&#41;;        myqueue.push&#40;75&#41;;          myqueue.back&#40;&#41; -= myqueue.front&#40;&#41;;        cout &lt;&lt; myqueue.back&#40;&#41; &lt;&lt; endl;        return 0;    &#125;
A. 12
B. 75
C. 63
D. None of the mentioned
Answer:A
#include &lt;iostream&gt;    #include &lt;queue&gt;      using namespace std;    int main &#40;&#41;    &#123;        queue&lt;int&gt; myqueue;        myqueue.push&#40;12&#41;;        myqueue.push&#40;75&#41;;          myqueue.back&#40;&#41; -= myqueue.front&#40;&#41;;        cout &lt;&lt; myqueue.back&#40;&#41; &lt;&lt; endl;        return 0;    &#125;
A. 12 B. 75 C. 63 D. None of the mentioned
Explanation:In this program, We used the queue operation and performed the back operation. Because of that operation, We got the output as 63.