A city is comparing the amount of time traffic lights stay green for two intersecting streets. The equations below represent the amount of time, y, that a light stays green on Snowy Lane and Ranger Avenue, respectively, as a function of the number of cars, x, that travel through the intersection. How many cars must pass through the intersection for the green lights of the two streets to last an equal amount of time? A,10 B,13 C,6 D,4