A European call option gives you the right to buy at a specified future date a share of stock for a given exercise price. A butterfly spread involves buying one call option with a low exercise price, buying one call option with a high exercise price, and selling two call options with an exercise price midway between the low and high exercise prices. Here is an example of a butterfly spread: The current stock price is $60. You buy a $54 six-month European call option for $9, buy a $66 six-month European call option for $4, and sell two $60 European call options for $6. Compute the profit (in dollars, not percentage) for this transaction as a function of six-month stock prices ranging from $40 to $80. When a trader purchases a butterfly spread, which type of movement in the stock price during the next six months is the trader betting on?