How to resolve ambiguity when argument is null?

Question

Compiling the following code will return The call is ambiguous between the following methods or properties error. How to resolve it since I can\'t explicitly co

Answer 1

Just an alternative solution I prefer

static void Main(string[] args)
{
    Func(Class1.NULL);
}

void Func(Class1 a)
{ }

void Func(Class2 b)
{ }

class Class1
{
    public static readonly Class1 NULL = null;
}

class Class2
{
    public static readonly Class2 NULL = null;
}