Which of the following CANNOT be used as an underlying datatype for an enum in C#.NET?

1. Every enum is derived from an Object class.
2. Every enum is a value type.
3. There does not exist a way to print an element of an enum as a string.
4. Every enum is a reference type.
5. The default underlying datatype of an enum is int.

1. An enum can be declared inside a class.
2. An enum can take Single, Double or Decimal values.
3. An enum can be declared outside a class.
4. An enum can be declared inside/outside a namespace.
5. An object can be assigned to an enum variable.

1. By default the first enumerator has the value equal to the number of elements present in the list.
2. The value of each successive enumerator is decreased by 1.
3. An enumerator contains white space in its name.
4. A variable cannot be assigned to an enum element.
5. Values of enum elements cannot be populated from a database.

int a = 10; 
int b = 20; 
int c = 30;
enum color: byte
{
    red = a, 
    green = b,
    blue = c 
}

namespace CuriousTabConsoleApplication
( 
class Sample
{ 
    private enum color : int
    { 
        red, 
        green, 
        blue
    }
    public void fun()
    {
        Console.WriteLine(color.red); 
    }
}
class Program
{ 
    static void Main(string[ ] args)
    { 
        // Use enum color here
    } 
} 
}

1. To define a variable of type enum color in Main(), we should use the statement, color c; .
2. enum color being private it cannot be used in Main().
3. We must declare enum color as public to be able to use it outside the class Sample.
4. To define a variable of type enum color in Main(), we should use the statement, Sample.color c; .
5. We must declare private enum color outside the class to be able to use it in Main().