                 digitalWrite(C, HIGH);
   }
 
-  if(ledNum == 3)
+  if(ledNum == 3)   // red_LED_01
   { 
                 pinMode(A, OUTPUT);
                 pinMode(B, OUTPUT);

                 digitalWrite(B, LOW);        
  }

  if(ledNum == 4)
  {
                pinMode(A, OUTPUT);
                pinMode(B, OUTPUT);

                //digitalWrite(C, LOW);
  }
  
  if(ledNum == 1)   // green_LED_01
  {
                pinMode(A, OUTPUT);
                pinMode(B, INPUT);  // changed to input to trigger tri state.
