A European call written on shares has strike price $12 and expires in six time steps. Using CRR notation, the underlying share prices are calculated using S=$14,u=1.2 and d=1/u. The return on a bank investment over each time step is R=1.05 Find the premium of an American put. Might a holder consider exercising the American put at any time prior to expiry? Explain why or why not. And if so, identify those nodes at which the holder might consider exercising the American put prior to expiry