On January 1, 2016, Riverbed Corporation granted 10,300 options to key executives. Each option wows the executive to purchase one share of Riverbed's $5 par valve common stock at a price of $20 per share. The options were exercisable within a 2-year period beginning January 1, 2018, if the grantee is still employed by the company at the time of the exercise. On the grant date, Riverbed's stock was trading at $26 per share, and a fair value option pricing model determines total compensation to be $413,000 On May 1, 2018, 8,240 options were exercised when the market price of Riverbed's stock was $30 per share. The remaining options lapsed in 2020 because executives dedded not to exercise their options Prepare the necessary Journal entries related to the stock option plan for the years 2016 through 2020. (Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry for the account titles and enter for the amounts.) Date Account Titles and Explanation Debit Credit 5/1/18