Answer:
The answer is C.
Explanation:
Active voice basically means that there is a subject performing the action given by the verb, there also has to be an object upon which this action is performed. ( I am making a cake. )
Contrary to that passive voice means that the object of an active sentence has become a subject. ( The cake is being made. )
We can see that the verb has changed its form to past participle.
Regarding your question, we have Joe (subject) who is supposed to reinforce (verb) the side of the cabin (object).
Whenever a sentence follows the pattern of subject, then verb, then object, it is in active voice, so the answer is C.
