Answer: B. An ordinance
Explanation: An ordinance can be simply refered to as an authoritative decree or order (authoritative saying). Ordinance mostly over see or governs issues which cannot be found in either the federal or state law, this might include issues related to public nuisance, zoning, construction regulation etc.
In the case of Flagstaff city that passes the legislation of regulating taking of alcohol on the street, this issue is a public matter as such the legislation should be refered to as an ordinance.
