Using a two-step binomial tree, calculate the value of an American call option where the underlying stock pays a dividend of $1 per share just before the options expiration. The stock is trading at $22, the strike is $20, the risk-free rate is 4%. The option is outstanding for another two years (each step in the binomial tree is one year long). The stock is expected to rise or fall 10% in each one-year period prior to expiry.

Can you please explain/show in Excel including formulas.