Declarations and Initializations - General Questions

What is the storage class of a local variable declared without any keyword?

What will be the output of the program?

#include <stdio.h>

int main(void) {
    int a[4] = {0};
    printf("%d %d\n", a[0], a[3]);
    return 0;
}

What will be the output of the program?

#include <stdio.h>
int x = 10;
int main(void) {
    int x = 20;
    printf("%d\n", x);
    return 0;
}

What will be the output of the program?

#include <stdio.h>

int main(void) {
    int a = 10, b = 3;
    printf("%d %d\n", a / b, a % b);
    return 0;
}

What will be the output of the program?

#include <stdio.h>

int main(void) {
    int x = 5;
    {
        int x = 10;
        printf("%d ", x);
    }
    printf("%d\n", x);
    return 0;
}