Answer:   Please have a look at below example -

namespace SingletonDemo
{
public sealed class Singleton
{
private static int counter = 0;
private static Singleton instance = null;
public static Singleton GetInstance
{
get
{
if (instance == null)
instance = new Singleton();
return instance;
}
}

private Singleton()
{
counter++;
Console.WriteLine("Counter Value " + counter.ToString());
}
public void PrintDetails(string message)
{
Console.WriteLine(message);
}
}
}

Answer:   In The singleton design pattern, only one Instance of a class will be created and will be used to provide access point globally
Below code will demonstrate the Singleton Design Pattern in C#
public sealed class Singleton
{
private static readonly Singleton obj = new Singleton();
}