C++ | Function Overloading and Default Arguments | Question 3

Which of the following overloaded functions are NOT allowed in C++? 1) Function declarations that differ only in the return type

    int fun(int x, int y);
         void fun(int x, int y); 

2) Functions that differ only by static keyword in return type

    int fun(int x, int y);
         static int fun(int x, int y); 

3)Parameter declarations that differ only in a pointer * versus an array []

int fun(int *ptr, int n);
int fun(int ptr[], int n); 

4) Two parameter declarations that differ only in their default arguments

int fun( int x, int y); 
int fun( int x, int y = 10);