#include &lt;stdio.h&gt;    int main&#40;&#41;    &#123;        int n;        scanf&#40;&quot;%d&quot;, &amp;n&#41;;        ungetc&#40;n, stdin&#41;;        scanf&#40;&quot;%d&quot;, &amp;n&#41;;        printf&#40;&quot;%d\n&quot;, n&#41;;        return 0;    &#125;
A. Compile time error
B. Whatever is typed by the user first time.
C. Whatever is typed by the user second time
D. Undefined behaviour
Answer:A
#include &lt;stdio.h&gt;    int main&#40;&#41;    &#123;        int n;        scanf&#40;&quot;%d&quot;, &amp;n&#41;;        ungetc&#40;n, stdin&#41;;        scanf&#40;&quot;%d&quot;, &amp;n&#41;;        printf&#40;&quot;%d\n&quot;, n&#41;;        return 0;    &#125;
A. Compile time error B. Whatever is typed by the user first time. C. Whatever is typed by the user second time D. Undefined behaviour