Question from the Language C - Fundamentals test

What can we say about the variable a?

int a = 20;
int main ()
{
int a = 10;
int b = 20;
show(a,b);
return 0;
}

void show(int a, int b) {
printf ("value of a %d /n", a);
printf ("value of b %d /n", b);
}