1 tire line. 185/50R16 tires sized to your wheels and your car.

A 185/50R16 is 185 mm wide with a 93 mm sidewall (50 series) on a 16 inch wheel, 23.3 inches tall overall. A tire size only makes sense next to a wheel width and a car. 185/50R16 mounts on a range of widths, and the overall height decides whether the speedometer and the fender stay happy.
1 line carries 185/50R16, from Continental Tire. By type that is 1 all season. 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 185/50R16 lines that do both.