What is the tyre size of BMW M Series?

BMW M Series is available in 8 tyre sizes - 255/40 R18,275/40 R18, 255/35 R19, 255/35 R19-275/35 R19, 275/40R19-285/40 R19, 265/40 R19,295/35 R19, 275/35R20-275/35 R20, 285/40 R20,325/35 R20 and 265/35 R20,295/30 R20.