Answer: diode
Explanation: A diode is an electronic device that has the ability to work in 1 direction of electric current.
At forward bias ( when the positive terminal of the diode is connected to the positive terminal of the source and negative terminal to the negative of the source) the diode allows current to flow thus acting as a close switch.
At reverse bias ( when the positive terminal of the diode is connected to the negative terminal of the source and the negative terminal of the diode to the positive terminal of the source) the diode stops question from flowing thus acting like an open circuit or an open switch
