"Public nuisance" means:
   A.   A condition which endangers safety or health, is offensive to the senses or obstructs the free use of property so as to interfere with the comfortable enjoyment of life or property by the city or any neighborhood found therein, or by a considerable number of persons; or
   B.   Any premises where persons gather for the purpose of engaging in unlawful conduct; or
   C.   A condition which renders dangerous for passage any public street, avenue, alley or public place or right of way, or waters used by the people of the city. (1975 Code § 8.02.010)