Which of the following statements correct about the below program?

#include<stdio.h>

int main()
{
    union a
    {
        int i;
        char ch[2];
    };
    union a u1 = {512};
    union a u2 = {0, 2};
    return 0;
}

1:	u2 CANNOT be initialized as shown.
2:	u1 can be initialized as shown.
3:	To initialize char ch[] of u2 '.' operator should be used.
4:	The code causes an error 'Declaration syntax error'