Answer: B) consult an attorney and put their agreement in writing.
Explanation:
As soon as they have agreed to form a partnership, they should put this on paper to finalize it properly and give it more legal standing.
They do this by consulting an attorney who will then put the agreement to writing. This agreement will show what is expected of both parties and will be fully enforceable. It would also help in filling the requisite documents for the formation of the music school.