1 tire line. 225/50R15 tires sized to your wheels and your car.

A 225/50R15 is 225 mm wide with a 113 mm sidewall (50 series) on a 15 inch wheel, 23.9 inches tall overall. A tire size only makes sense next to a wheel width and a car. 225/50R15 mounts on a range of widths, and the overall height decides whether the speedometer and the fender stay happy.
1 line carries 225/50R15, from Toyo. By type that is 1 performance summer. The tire has to stay near your car's stock height and mount on your wheel width, so pick the car and the wheel set and the page keeps only the 225/50R15 lines that do both.