Three cars arrive at an intersection at the same time. Who here has the right-of-way?

Pedestrians have the right-of-way when they are about to, or already have, entered a crosswalk. Not all crosswalks have pavement markings, and not all crosswalks are on street corners. So here, the pedestrian has the right-of-way. Car B may proceed since it is not crossing the pedestrian's path. [6.1.1 - Safety Rules for Motorist Regarding Pedestrians, 6.1 Pedestrians, Section 6 Sharing the Road, Florida Driver's Handbook]