Access Modifier in C#

Well the access modifier are the reserve keywords which define the access right and scope of access the entity.Objects in .NET are created from a class, struct, etc. These definitions, as well as the properties, methods, or events within them, use an access modifer that determines who can access it. A class or structure outside of the current class definition or even the in different projects have different access rights depending on the type of accessor used. Take a look at the accessors below:
public
This makes the member visible globally
Eg. class Gremlin { public Gremlin spawn() { return new Gremlin(); } }

protected
This makes the member visible to the current class and to child classes. Protected members are only accessible in the same class or through inherited classes.
Eg. class ParentClass { protected int valueA; }
class ChildClass { public void doSomething() { valueA = 3; } }

private
This makes the member visible only to the current class.
Eg. class MyCollection { private int lastIndex; }

internal / Friend
This makes the member visible within the same assembly.
Eg. internal class ProprietaryStuff { }

protected internal / Protected Friend
A combination of protected and internal. This makes the member visible within the same assembly and also makes the member visible to an inheriting class. An inheriting class does not need to be in the same assembly to access the member.