Is implementation of a standard constructor (Java) necessary in this case?

I have three classes like this:

public abstract class ClassA extends ClassX {
    protected ClassA() {
        super();
    }
    // more code
}
public class ClassB extends ClassA {
    public ClassB() {
        super();
    }
    // more code
}
public abstract class ClassC extends ClassB {
    public ClassC() {
        super();
    }
    // more code
}

I would say that the standard constructor for ClassC is not necessary since Java will insert it during compilation, since there is no other constructor in this class, right? If true, I could simplify the code for ClassC down to this:

public abstract class ClassC extends ClassB {
    // more code
}

Now I'd say that I can't do the same for ClassB since the accessibility of the constructor is increased from protected to public.

I'm asking since I am not 100% sure about this and thought I might be missing something. Especially about the standard constructor that will be inserted into ClassC if I don't implement it myself. In this case it will have accessibility public since it inherits from ClassB. Is that correct?

So my question is: Can I delete the constructor in ClassC without having the code being changed (especially the accessibility of constructors) and is it correct that I can't delete the constructor of ClassB.