Typedef - General Questions

What will be the output of the program?

#include <stdio.h>
typedef int (*Op)(int, int);
int add(int a, int b) { return a + b; }
int main(void) {
    Op f = add;
    printf("%d\n", f(2, 3));
    return 0;
}

What will be the output of the program?

#include <stdio.h>
typedef struct Node {
    int v;
    struct Node *next;
} Node;
int main(void) {
    Node b = {2, NULL}, a = {1, &b};
    printf("%d\n", a.next->v);
    return 0;
}

What will be the output of the program?

#include <stdio.h>
typedef char *Str;
int main(void) {
    Str a = "hi", b = "yo";
    printf("%s %s\n", a, b);
    return 0;
}

What will be the output of the program?

#include <stdio.h>
typedef int Marks;
int main(void) {
    Marks m = 95;
    printf("%d\n", m);
    return 0;
}

Which standard type is defined with typedef?