Which Gang of Four design pattern is shown below?
public class A 
{
    private A instance;
    private A() 
    { 
    }
    public static A Instance 
    {
       get
       {
           if ( A == null )
                A = new A();
           return instance;
       }
    }
}
							Options
 - Factory
 - Abstract Factory
 - Singleton
 - Builder
							CORRECT ANSWER :   Singleton 
                            
                            
			        
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