title: C#: constructor of nested class makes "inaccessible due to protection level"
body: <p>I have this piece of code, and error is generated, just because I haved added into a constructor for its class.</p>
  
  <pre><code>class NestedClass
  {
     class A
     {
        A() {}
     }
  
     class B
     {
         // no constructor
     }
  
     public static void run()
     {
       A a = new A();  // error
       B b = new B(); // no error
     }
  }
  </code></pre>
  
  <p>And error is:</p>
  
  <pre><code>NestedExample.A is inaccessible due to protection level
  </code></pre>
  
  <p>Please help me explain this.</p>
  
  <p>Thanks :)</p>