Covariant return types

Here's a class hierarchy:

class SuperClass {
    
    public A method1() {
        return new A();
    }
    
    public B method2() {
        return new B();
    }
}

class SubClass1 extends SuperClass {
    
    @Override
    public C method1() {
        return new C();
    }
}

class SubClass2 extends SubClass1 {
    
    @Override
    public B method1() {
        return new B();
    }
    
    @Override
    public D method2() {
        return new D();
    }
}

Repair the hierarchy of A, B, C, D according to the covariant return types principle.