Which of the following function is used to find the first occurrence of a given

Which of the following function is used to find the first occurrence of a given string in another string?

2) Which is more appropriate for reading in multi-word string?

3) What will be the output of the program ?

 #include<stdio.h>
 int main()
 {
     printf(2+"C Programming MCQ on Study 2 Online\n");
     return 0;
 }

4) What will be the output of the program ?

 #include<stdio.h>
 #include<string.h>
 int main()
 {
     char str[] = "Study 2 Online\0 C Language MCQ\0";
     printf("%s\n", str);
     return 0;
 }

5) What is the output of this C code?

#include <stdio.h>
     int main()
     {
         char *str = "hello, world\n";
         printf("%d", strlen(str));
       }