Which bitwise operator is suitable for turning on a particular bit in a number?

Which bitwise operator is suitable for turning on a particular bit in a number?

2) What is the output of this C code?

 #include <stdio.h>
     int main()
     {
         int a = 10, b = 5, c = 5;
         int d;
         d = a == (b + c);
         printf("%d", d);
     }

3) A typecast is used to:

4) What is the output of this C code?

#include <stdio.h>
     void main()
     {
         char a = 'a';
         int x = (a % 10)++;
         printf("%d\n", x);
     }

5) Which among the following are the fundamental arithmetic operators, ie, performing the desired operation can be done using that operator only?