限制对象的创建

我在这里有一个很奇怪的问题。我有Class A，Class B和ClassC。我想创建Class B的对象，它可以创建A的对象。但是如何限制Class C从创建Class A的对象。

I have a very strange question here. I have Class A, Class B and Class C. I want to create object of Class B which can create the object of A. But how to restrict Class C from creating object of Class A.

一种方法是在B类中定义A类，以便只有B类可以创建A类的实例，而C类不能访问A类。

One way is define Class A inside Class B, so that Only Class B can create the instance of Class A and Class C cannot access Class A.

但是，我认为嵌套是错误的方法。

But, I think nesting is a wrong way.

我们有什么方法可以限制对象的创建吗？是否可以使用属性和反射来帮助限制？

Do we have any way to restrict the object creation? Is it possible to use attribute and reflection to help to restrict? If possible is there a recommended way?

请分享您的想法。