Understanding how different factors affect the value of options is the first step to understanding option pricing models. When all other things are held constant, an option on an extremely volatile share of stock is worth ___ than an option on a less volatile share of stock. As the exercise price of a call option increases, the price of the call option will ___. However, as the length of the option period ___, the call option price will increase. The call option price will decrease when the price of the underlying stock ___. Which of the following best describes a naked option? When an investor sells call options without the stock to back them up When an investor writes call options against stock held in his or her portfolio