#include&lt;stdio.h&gt;   #include&lt;stdlib.h&gt;&nbsp;   int main&#40;&#41;   &#123;       int *ptr;       ptr = &#40;int*&#41;malloc&#40;sizeof&#40;int&#41;*4&#41;;       ptr = realloc&#40;ptr,sizeof&#40;int&#41;*2&#41;;       return 0;   &#125;
A. 2
B. 4
C. 8
D. none of the mentioned
Answer:A
#include&lt;stdio.h&gt;   #include&lt;stdlib.h&gt;&nbsp;   int main&#40;&#41;   &#123;       int *ptr;       ptr = &#40;int*&#41;malloc&#40;sizeof&#40;int&#41;*4&#41;;       ptr = realloc&#40;ptr,sizeof&#40;int&#41;*2&#41;;       return 0;   &#125;
A. 2 B. 4 C. 8 D. none of the mentioned
Explanation:We can also use the realloc() to make memory block smaller.