Which of the following statements are correct about an if-else statements in a C-program?

1:	Every if-else statement can be replaced by an equivalent statements using   ?: operators
2:	Nested if-else statements are allowed.
3:	Multiple statements in an if block are allowed.
4:	Multiple statements in an else block are allowed.

#include<stdio.h>
int main()
{
    int i = 10, j = 20;
    if(i = 5) && if(j = 10)
        printf("Have a nice day");
    return 0;
}

#include<stdio.h>
int main()
{
    int x = 10, y = 100%90, i;
    for(i=1; i<10; i++)
    if(x != y);
        printf("x = %d y = %d\n", x, y);
    return 0;
}

#include<stdio.h>
int main()
{
    int i = 0;
    i++;
    if(i <= 5)
    {
        printf("CuriousTab\n");
        exit(0);
        main();
    }
    return 0;
}

#include<stdio.h>
int main()
{
    int i = 10, j = 15;
    if(i % 2 = j % 3)
        printf("CuriousTab\n");
    return 0;
}

#include<stdio.h>
int main()
{
    float d=2.25;
    printf("%e,", d);
    printf("%f,", d);
    printf("%g,", d);
    printf("%lf", d);
    return 0;
}

#include<stdio.h>
int main()
{
    float *p;
    printf("%d\n", sizeof(p));
    return 0;
}

#include<stdio.h>
int main()
{
    float a=0.7;
    if(a < 0.7f)
        printf("C\n");
    else
        printf("C++\n");
    return 0;
}

#include<stdio.h>
int main()
{
    float a=0.7;
    if(a < 0.7)
        printf("C\n");
    else
        printf("C++\n");
    return 0;
}