Task: Class Definition Understanding (ontology: Sciences/Biology)

Which of the following definitions best describes '4-hydroxy-2-quinolone'?

A. A heteroaryl hydroxy compound that is 2-quinolone substituted at position 4 by a hydroxy group.
B. A quinolone that is 4-oxo-1,4-dihydroquinoline-3-carboxylic acid which is substituted at positions 1, 6, 7 and 8 by cyclopropyl, fluoro, hexahydropyrrolo[3,4-b][1,4]oxazin-6-yl and cyano groups respectively; an antibiotic used for treatment of acute otitis externa (swimmer's ear) caused by the bacteria Pseudomonas aeruginosa and Staphylococcus aureus.
C. An organosulfonic acid that is ciprofloxacin carrying a sulfo group at position 4 of the piperazine ring. It is a metabolite of ciprofloxacin.
D. A quinolone that is 4-quinolone substituted at positions 2 and 3 by hydroxy and carboxy groups respectively.

Answer: A heteroaryl hydroxy compound that is 2-quinolone substituted at position 4 by a hydroxy group.