Answer: At common law, Designer fashion can either sue or wait for Delaney's wrist to get healed.
Explanation: Common laws are sets of unwritten laws established by judges or courts. These laws are not backed by the legislative. One can say they are "common sense".
In this case, Common sense will say that designer fashion has a right to sue or wait since it's a contractual agreement.
If I was to advise designer fashion, I'd say they wait as the injury is an unforeseen circumstance.