Assume that on January 1, year 1, XYZ Corp. issued 1,000 nonqualified stock options with an estimated value of $3.60 per option. Each option entitles the owner to purchase one share of XYZ stock for $14 a share the per share price of XYZ stock on January 1, year 1 when the options were granted). The options vest 25 percent a year (on December 31) for four years (beginning with year 1). All 500 stock options that had vested to that point were exercised in year 3 when the XYZ stock was valued at $21 per share. No other options were exercised in year 3 or year 4. What is the book-tax difference associated with the stock options in Yoar Three? (enter a favorable difference as a positive and an unfavorable difference as a negative)