A wrong question in Sololearn game (C++)?

Question

I got the following question in Sololearn game:

A derived class doesn't inherit access to which of the followings of a base class?
(+) Private data
(+) Friend functions
(-) Protected data
(+) Overloaded operators

Answer #1:
I agree, a derived class can not access to private data of a base class.

Answer #2:
friend functions for classes is usual functions: if a function was defined before use it may be used. Vice versa, friend functions have access to all class data. So, an inheritance can't change an access to friend functions from a class.
I think that the author of the question meant that base class friend functions don't have access to derived class data.
If so, I agree, but think it is better to rewrite the answer#2 or the question.

Answer #3:
I agree, a derived class can access to protected data of a base class.

Answer #4:
I disagree.
Here, I can't guess what the author meant.
Overloaded operators that were declared as class methods are inherited according their access specifiers (only protected and public). In that case, the answer#4 is wrong.
Overloaded operators that were declared as standalone functions don't belong to the class, and so, access to them is defined as to a usual function (if it was declared before use, it may be used). In that case, answer#4 is also wrong.

What do you think?

P.S.
I marked it as wrong 2 or 3 weeks ago, but got it again.
Appologize in advance to the author of the question, if I was wrong.

Answer 1

Screenshot of the question:
https://drive.google.com/file/d/19A0qzrQNxCMZpHAhEQnxkpxDpE2h8kTw/view?usp=sharing

It is the result. Sololearn showed which answers must be selected.

Answer 2

@Hatsy Rei
I sent complaint 2 or 3 weeks ago (using send complaint button), but got that wrong question again.

operator=() is also inherited by derived class (if it was decalred and has public or protected access specifiers). It is just hidden by default assignment operator of a derived class.

But you can call it, for example, like this:

class A{
int x = 0;
public:
A&operator=(int value){ x = value; return *this; };
int getX() const { return x; }
};

class B: public A{};

int main()
{
A a;
B b;

a = 3;
b.A::operator=(5);

cout << a.getX() << endl;
cout << b.getX() << endl;

return 0;

}

the output will be 3 5.

If operator=() were not inherited, there would be an error in this code.
There is no way to call not inherited methods.

https://code.sololearn.com/cfs8X0f0S6zg

Answer 3

According to

https://docs.microsoft.com/en-us/cpp/cpp/general-rules-for-operator-overloading?view=vs-2019

"All overloaded operators except assignment (operator=) are inherited by derived classes."

The quiz answer does appear to be wrong, at least for all other operators except =. I did a little test and sure enough,

class A {
public: int operator+(int y) { return y; }
};
class B : public A {};

int main() { std::cout << B()+39; }

Unless the quiz is asking about something else, perhaps a completely different question than what we perceive from its wording, a fix is likely needed. If you've flagged the question but it remains unrectified, perhaps consider notifying the administrators directly using the in-app feedback feature or through mail. Linking this thread should help.

[e-mail]

Answer 4

Can you post a screenshot?