F is employed by a public corporation. In year 1, F was granted a stock option to acquire 1,000 shares from the treasury of her employer's corporation for $8 a share. At the time of receiving the option, the shares were valued at $10 per share. In year 3, F exercised the option and purchased 1,000 shares for $8,000. At the purchase date, the shares were valued at $15 per share. In year 5 F sold 1,000 shares for $20 per share. What amount is included in F's employment income for tax purposes in year 1? $