What will be the output of the following C code?#include

What will be the output of the following C code?

#include <stdio.h>
    int main()
    {
        int num;
        scanf("%d", num);
        printf("%d\n", num);
        return 0;
    }

1. Whatever user types
2. Compilation Error
3. Depends on the standard
4. Undefined behavior
5. None of these

Undefined behavior