What will be the output of the following C code?

#include <stdio.h>
#define hello( n ) printf( "a" #n "= %d", a##n )
int a3=3;
int main()
{
    #ifdef a3
       hello(3);
   #else
       printf("sorry");
   #endif
}

A. Compile C code B. Optimize code C. Preprocess code before compilation D. Execute code

A. #define B. #include C. #ifdef D. #pragma

A. To include a header file B. To define a macro C. To declare a constant D. To declare a variable

A. #ifdef B. #ifndef C. #if D. #else