question: hydrogen:oxygen:water
choices.label: A B C D
choices.text: root:leaf:flower yellow:blue:green land:ocean:sky oil:coal:natural gas
explanation: "hydrogen" and "oxygen" are part of "water". "root" and "leaf" and "flower" are part of the plant, "root" and "leaf" are not part of the "flower". "yellow" and "blue" are part of "green". "land" and "ocean" and "sky" are part of the earth, "land" and "ocean" are not part of the "sky". "oil" and "coal" and "natural gas" are part of fossil fuels, "oil" and "coal" are not part of "natural gas".
relation: hydrogen oxygen R2.3
relation: hydrogen water R2.3
relation: root leaf flower R2.4
relation: yellow blue R2.3
relation: yellow green R2.3
relation: land ocean sky R2.4
relation: oil coal natural gas R2.4