Two analogies that relate actions to the tools used to perform the action is given in the form "A : B. C : ?". "A : B" relates action A to tool B. Your task is to replace the question mark (?) with the appropriate tool for the given action C, following the "A : B" relation.

Q: wash : soap. unlock : ?

A: key
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Q: mop : mop. wash : ?

A: soap
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Q: unlock : key. pull : ?

A:
pliers
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