TASK DEFINITION: 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.
PROBLEM: wash : rag. unlock : ?

SOLUTION: key

PROBLEM: eat : spoon. mop : ?

SOLUTION: mop

PROBLEM: stir : spoon. spread : ?

SOLUTION:
knife