No, Derived classes cannot have greater accessibility than their base types. For example the FOLLOWING code is illegal. using System;
internal class InternalBaseClass
{
public void Print()
{
Console.WriteLine("I am a Base Class Method");
}
}
public class PublicDerivedClass : InternalBaseClass
{
public static void Main()
{
Console.WriteLine("I am a Public Derived Class Method");
}
}

When you compile the above code an error will be generated stating "INCONSISTENT accessibility: base class InternalBaseClass is less accessible than class PublicDerivedClass".To make this SIMPLE, you cannot have a public class B that DERIVES from an internal class A. If this were allowed, it would have the effect of making A public, because all protected or internal members of A are accessible from the derived class.

No, Derived classes cannot have greater accessibility than their base types. For example the following code is illegal. using System;
internal class InternalBaseClass
{
public void Print()
{
Console.WriteLine("I am a Base Class Method");
}
}
public class PublicDerivedClass : InternalBaseClass
{
public static void Main()
{
Console.WriteLine("I am a Public Derived Class Method");
}
}

When you compile the above code an error will be generated stating "Inconsistent accessibility: base class InternalBaseClass is less accessible than class PublicDerivedClass".To make this simple, you cannot have a public class B that derives from an internal class A. If this were allowed, it would have the effect of making A public, because all protected or internal members of A are accessible from the derived class.