#include&lt;stdio.h&gt;   #include&lt;fcntl.h&gt;&nbsp;   int main&#40;&#41;   &#123;       int fd, count;       char ch;       fd = open&#40;&quot;sanfoundry.txt&quot;,O_RDWR|O_CREAT&#41;;       write&#40;fd,&quot;s&quot;,1&#41;;       lseek&#40;fd,0,SEEK_SET&#41;;       write&#40;fd,&quot;d&quot;,1&#41;;       lseek&#40;fd,0,0&#41;;       read&#40;fd,&amp;ch,1&#41;;       printf&#40;&quot;%c\n&quot;,ch&#41;;       return 0;   &#125;
A. d
B. s
C. sd
D. none of the mentioned
Answer:A
#include&lt;stdio.h&gt;   #include&lt;fcntl.h&gt;&nbsp;   int main&#40;&#41;   &#123;       int fd, count;       char ch;       fd = open&#40;&quot;sanfoundry.txt&quot;,O_RDWR|O_CREAT&#41;;       write&#40;fd,&quot;s&quot;,1&#41;;       lseek&#40;fd,0,SEEK_SET&#41;;       write&#40;fd,&quot;d&quot;,1&#41;;       lseek&#40;fd,0,0&#41;;       read&#40;fd,&amp;ch,1&#41;;       printf&#40;&quot;%c\n&quot;,ch&#41;;       return 0;   &#125;
A. d B. s C. sd D. none of the mentioned
Explanation:Because of “lseek” system call the character “s” is overwritten by character “d” in the file “sanfoundry.txt”.