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.

Let me give you an example: eat : fork. cook : ?
The answer to this example can be: pan
Here is why: The given analogy relates actions to the tools used to perform them. A fork can be used to eat. To cook, a pan can be used.

OK. solve this:
scrub : brush. wash : ?
Answer:
soap