Please use C language.

4. (25 points) Answer the following questions. a. (15 pts) The program given below uses a switch-case statement. Re-write the program converting the switch-case statement into an if-else statement. #include void main int num; scanf("%d",&num); switch(num) case 1: num-num + 5 break; case 2: case 4: num- num * 2: break; case-1: num= 0; break; default: num=-1; 3 printf("The result is %d ",num); } b. (10 points) (WHO) The age health scale of the world health organization is given below. 0 - 17 adolescents.(ergen) 18 - 65 teen (gen) 66 - 79 middle aged (ortayal) 80 - 99 old. (yal) The age of a person is entered on the keyboard. Write main routine which does given procedure