Hye... can explain to me how to switching with 3 led?there are red,yellow, and green. When the probe 1, is touched,green turn on... then,when probe 2 is touched, yellow turn on and green turn off... when probe 3 is touched, red turn on,yellow and green is turn off... please help for this week bcause 4 my final projects...

Can you provide more detail, Many ways as you describe?
When you touch probe to finger or to LED(s)
You could use a tricolored LED.
Red is One polarity, green is opposite polarity, and yellow is AC Voltage applied.
Is their a maximum or minim of parts to be used?