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]: iron : iron. drill : ?
[A]: drill


[Q]: wash : rag. unlock : ?
[A]: key


[Q]: scrub : brush. iron : ?
[A]:
iron