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;
    printf("%d\n", scanf("%d", &i));
    return 0;
}

int *ptr[30];

#include<stdio.h>

int main()
{
    char huge *near *far *ptr1;
    char near *far *huge *ptr2;
    char far *huge *near *ptr3;
    printf("%d, %d, %d\n", sizeof(ptr1), sizeof(ptr2), sizeof(ptr3));
    return 0;
}

#include<stdio.h>

int main()
{
    struct node
    {
        int data;
        struct node *link;
    };
    struct node *p, *q;
    p = (struct node *) malloc(sizeof(struct node));
    q = (struct node *) malloc(sizeof(struct node));
    printf("%d, %d\n", sizeof(p), sizeof(q));
    return 0;
}

#include<stdio.h>

int main()
{
    int arr[] = {12, 13, 14, 15, 16};
    printf("%d, %d, %d\n", sizeof(arr), sizeof(*arr), sizeof(arr[0]));
    return 0;
}

void *cmp();