On October 15, 2012, the board of directors of Ensor Materials Corporation approved a stock option plan for key executives. On January 1, 2013, 23 million stock options were granted, exercisable for 23 million shares of Ensor's $1 par common stock. The options are exercisable between January 1, 2016, and December 31, 2018, at 90% of the quoted market price on January 1, 2013, which was $20. The fair value of the 23 million options, estimated by an appropriate option pricing model, is $6 per option. 2.3 million options were forfeited when an executive resigned in 2014. All other options were exercised on July 12, 2017, when the stock's price jumped unexpectedly to $22 per share. Required:

1. When is Ensor