McDonald's has installed self$-$service ordering kiosks, how does that affect McDonald's demand for workers and why?

McDonald's demand for labor will remain unchanged.

McDonald's demand for workers will rise, as they will need to hire workers to assist customers while they order from the kiosk.

McDonald's demand for workers will fall, as the ordering kiosks are a complement for cashiers.

McDonald's demand for workers will fall, as the ordering kiosks are a substitute for cashiers.