"Both" Wheel Sizes

Wheel size at the 4L point is a crossover point. In a Competition model that will be run with narrow tires and no fenders, a 700c wheel can be used on this size. For a Touring or Sport model that is designed for wider tires and fenders, a smaller wheel is necessary to avoid dangerous toe overlap.

To read about why smaller wheels are often better for smaller bikes, I've written extensively on the subject.