What is the output of this program?

#include<stdio.h>
#include<fcntl.h>
 
int main()
{
    int fd, count;
    fd = open("demo.txt",O_WRONLY|O_CREAT);
    count = write(fd,"Linux System Programming",5);
    if(count != 5)
        perror("write");
    return 0;
}

A. countw B. wcount C. wc D. count p E. None of the above

A. dm B. rm C. delete D. erase E. None of the above

A. rdir B. remove C. rd D. rmdir E. None of the above

A. x B. y C. a D. z E. None of the above