question: engine:aircraft:passenger
choices.label: A B C D
choices.text: keys:piano:music battery:torch:light clockwork:clock:time steelyard:weighbeam:weight
explanation: the "engine" is a part of the "aircraft", the "engine" is its power source, and the "aircraft" carries the "passengers". the "keys" are part of the "piano", but not the source of its power. "battery" and "torch" need to be used together. "clockwork" is a part of "clock", "clockwork" is its power source. "clock" displays "time". "weighbeam" is part of "steelyard", and the order of words is inconsistent with the query.
relation: engine aircraft R2.3
relation: aircraft passenger R4.4
relation: keys piano R2.3
relation: battery torch R3.10
relation: clockwork clock R2.3
relation: clock time R4.4
relation: steelyard weighbeam R2.3