  Options financial instruments designed to protect investors from the stock
market randomness. In 1973, Fisher Black, Myron Scholes and Robert Merton
proposed a very popular option pricing method using stochastic differential
equations within the Ito interpretation. Herein, we derive the Black-Scholes
equation for the option price using the Stratonovich calculus along with a
comprehensive review, aimed to physicists, of the classical option pricing
method based on the Ito calculus. We show, as can be expected, that the
Black-Scholes equation is independent of the interpretation chosen. We
nonetheless point out the many subtleties underlying Black-Scholes option
pricing method.
