Why does the size of a derived class include private members from the base class?

Question

I have the following code:

class A {
  private:
    int i;
 };

class B : public A {
 private:
  int j;
 };

When I check sizeof(B)

Answer 1

It is inherited - the derived class object will contain it, but it can't be accessed by member functions of the derived class.