What are the access levels for class elements in object-oriented programming?

In object-oriented programming in C#, the following are the main access levels for class members:

• public — access is open to all, members are accessible from any code.
• private — access is restricted to within the class itself.
• protected — access is allowed within the class and its descendants.
• internal — access is allowed within the current assembly.
• protected internal — access is allowed either from the current assembly or from derived classes.
• private protected — access is allowed from derived classes, but only within the current assembly.

Example:

class Example
{
    public int PublicField;       // Accessible everywhere
    private int PrivateField;     // Only within Example
    protected int ProtectedField; // In Example and descendants
    internal int InternalField;   // Within the assembly
}