Protected Member
Protected Member of a class in only available in the contained class (in
which it has been declared) and in the derived class within the assembly and
also outside the assembly.
Means if a class that resides outside the assembly can use the protected
member of the other assembly by inherited that class only.
We can exposed the Protected member outside the assembly by inherited that
class and use it in the derived class only.
Note: Protected members are not accessible using the object in the derived class.
Internal Member
Internal Member of a class is available or access within the assembly
either creating object or in a derived class or you can say it is accessible
across all the classes within the assembly.
Note: Internal members not accessible outside the assembly either using
object creating or in a derived class.
Protected Internal
Protected Internal access modifier is combination Protected or Internal.
Protected Internal Member can be available within the
entire assembly in which it declared
either creating object or by inherited that class. And can be accessible outside
the assembly in a derived class only.
Note: Protected Internal member works as Internal within the same assembly and works as Protected for outside the assembly.