Which of the following statement is correct?

Which of the following statements are correct ?
1:A string is a collection of characters terminated by ''.
2:The format specifier %s is used to print a string.
3:The length of the string can be obtained by strlen().
4:The pointer CANNOT work on string.

Which of the following statements are correct about the below declarations?
char *p = "Sanjay";
char a[] = "Sanjay";

1: There is no difference in the declarations and both serve the same purpose.

2: p is a non-const pointer pointing to a non-const string, whereas a is a const pointer pointing 

    to a non-const pointer.

3: The pointer p can be modified to point to another string, whereas the individual characters within 

   array a can be changed.

4: In both cases the '' will be added at the end of the string "Sanjay".

Which of the following statements are correct about the program below?

#include<stdio.h>

int main()
{
    char str[20], *s;
    printf("Enter a string\n");
    scanf("%s", str);
    s=str;
    while(*s != '\0')
    {
        if(*s >= 97 && *s <= 122)
            *s = *s-32;
        s++;
    }
    printf("%s",str);
    return 0;
}

What will be the output of the following program in 16 bit platform assuming that 1022 is memory address of the string "Hello1" (in Turbo C under DOS) ?

#include<stdio.h>

int main()
{
    printf("%u %s\n", &"Hello1", &"Hello2");
    return 0;
}