Puzzle SL9

What does the following code write to the monitor?

#include <stdio.h>

int main( void )
{
  int a=1 ;
  printf("scope m: a=%d\n", a );

  if ( a )
  {
    int b = 2;
    printf("scope 1: a=%d\tb=%d\n", a, b );
    
    if ( b )
    {
      int c = 3;
      printf("scope 2: a=%d\tb=%d\tc=%d\n", a, b, c );
      a = b = c = 99;
      printf("scope 2: a=%d\tb=%d\tc=%d\n", a, b, c );
    }
    printf("scope 1: a=%d\tb=%d\n", a, b );
  }
  printf("scope m: a=%d\n", a );

  return 0 ;
}

This puzzle is not particularly tricky (like the last one). Just routine application of the rules will do.