Which of the following is true regarding the Black-Scholes formula? I) The binomial solution converges to the Black-Scholes formula when taking infinite number of steps. II) The Black-Scholes formula can be also applied to other underlying assets such as foreign currencies. III) The Black-Scholes formula can only be applied to European option, not American one. IV) There is general no simple formula comparable to the Black-Scholes formula to price American options.