What must a driver do at this white regulatory sign?

Correct answer: A – Pass to the right of the median, island, or obstruction
This is the KEEP RIGHT symbol sign. It directs traffic to pass on the right side of a median, island, pier, or similar obstruction. It is not the same as the separate SLOWER TRAFFIC KEEP RIGHT sign, which addresses lane use rather than passing an obstruction.
Source: Arizona Manual of Approved Signs — R4-7, “Keep Right (Symbol)”, MUTCD with Arizona Supplement — § 2B.39, “Keep Right and Keep Left Signs”


