An American asset-or-nothing call option (with parametersK,Fand expiration timet) can be exercised any time up tot. If the security's price when the option is exercised isKor higher, then the amountFis returned; if the security's price when the option is exer- cised is less thanK, then nothing is returned. Explain how you can use the multiperiod binomial model to approximate the risk-neutral price of an American asset-or-nothing call option.