Tipul struct la  examenul de bacalaureat

Varianta 1
struct punct
{
    float x,y;
};
punct A,B,C;

Varianta 2

struct punct
{
    float x,y;
};

struct punct A,B,C;

Varianta 3

struct punct
{
    float x,y;
} A,B,C;

Varianta 4

struct
{
    float x,y;
} A,B,C;

EX:
    struct
    {
        char nume[21];
        struct
        {
            int zi,luna,an;
        } dn;
        float mg;
    }E;