In 1), 3) the address of somewhere in the static data area will be returned.
But in 2), p is the address of the array, which is allocated on the stack and in one stack frame. After the function 'v()' is returned the stack frame
is removed (or become invalid), thus the address of the array (i.e. 'p') becomes an invalid address.

syntaxly , 2 is wrong, because it try to return memory on the stack, when v() is finished the the memory on stack is released. the returned pointer ref to invalid memory.
1 and 3 are exactly the same except in debug build 1 will alloc one pointer on stack, in optimized mode, these 2 function will all probably return a constant address,semanticly, 1&3 are all wrong. The string "result of function v()" is allocated by compiler in Initialized data segement, but, notice, logically, it should be constant,although u can modify it.
const char^ v()
{
return "result of function v()";
}
will be the best way

But from the article I have read: 3 is wrong too. I am really confused.

) Fairly Easy. What is wrong with the following function? Explain.

char* GetName()
{
return "Bill Clinton";
}

Answer: The string "Bill Clinton" is allocated on the stack and thus deallocated when the function returns. The function returns a pointer that cannot be trusted, aka a bad pointer.

1 , The pointer P you defined in the function is a local variable , so it will return NULL. in this case.
2. The same as number 1.
3. The function needs you return pointer , but you give it a string value.
The solutions is either:
char* v(char* p)
{
char p[] = " result of function v()";
return p;
} This one is better
or
char* v()
{
static p[]="result of function v()";
return p;
} It is ok.