This is honestly some of the most confusing route signage I've encountered. Bing Streetside is very good here, but it's not helping much :)

This view is on Paris Road south of Ammonette Street looking north. It shows a B sign with a double arrow pointing north on Paris and east on Ammonette. https://www.bing.com/maps?cp=38.962481%7E-92.312357&lvl=19.1&mo=om.1&pi=-1.8&style=x&dir=37.9

This one is on Business I-70 looking west. It shows a B sign pointing up the one-way ramp toward Paris Road. I feel like this one has an implied "TO" banner above the route sign. https://www.bing.com/maps?cp=38.96388%7E-92.309805&lvl=19.8&mo=om.1&pi=1.8&style=x&dir=270.6

MoDOT open data shows B following Paris Road southwest to MO 763... I think that's wrong.