Which piece of code below does NOT contain an obvious problem?

Question 2 Which piece of code below does NOT contain an obvious problem? How about this? int& func(int x) { return x; } This is correct? int func(const int &x) { return ++x; } Probably this is working? int* func(int x) { return &x; } Likely to be this? int func(int *x) { return x; } Maybe this one? int& func(int *x) { return *x; }