question: oxygen:life
choices.label: A B C D
choices.text: lighting:darkness vibration:sound effort:success candlelight:romantic
explanation: only "oxygen" can have "life". "darkness" will be dispelled by "light". only "vibration" can have "sound". "effort" leads to "success". a "romantic" atmosphere can be created by "candlelight".
relation: oxygen life R5.4
relation: lighting darkness R3.10
relation: vibration sound R5.4
relation: success effort R5.1
relation: candlelight romantic R3.10