Challenge: Roundabout: who has priority?

Every roundabout you have ever driven probably had sign B6 and shark's-teeth markings at the entry — so your reflex says: 'traffic on the roundabout always goes first.' The CBR exam designer knows you have that reflex, and tests exactly the roundabout with no sign at all. The book does not give an exception to the main rule here — it gives a SECOND rule that only applies when the first one is absent.