G is employed by a Canadian-controlled private corporation. In year 1, G was granted a stock option to acquire 2,000 shares from the treasury of his employers corporation for $9 a share. At the time of receiving the option, the shares were valued at $11 per share. In year 3, G exercised his option and purchased 2,000 shares for $18,000. At the purchase date in year 3, the shares were valued at $14 per share. In year 6, G sold 2,000 shares for $19 per share. What amount is included in Gs employment income for tax purposes in year 6?

Please provide a proper explanation for the answer.