On October 15, 2020, the board of directors of Ensor Materials Corporation approved a stock option plan for key executives. On January 1, 2021, 18 million stock options were granted, exercisable for 18 million shares of Ensor's $1 par common stock. The options are exercisable between January 1, 2024, and December 31, 2026, at 80% of the quoted market price on January 1, 2021, which was $15. The fair value of the 18 million options, estimated by an appropriate option pricing model, is $6 per option. Ensor chooses the option to recognize forfeitures only when they occur. Ten percent (2.8 million) of the options were forfeited when an executive resigned in 2022. All other options were exercised on July 12, 2025, when the stock’s price jumped unexpectedly to $26 per share.

Required:
a. When Is Ensor's stock option measurement date?
b. Determine the compensation expense for the stock option plan In 2021.
c. prepare the Journal entries to reflect the effect of forfeiture of the stock options on Ensor's financial statements tor 2022 and 2023.
d. Prepare the Journal entry to account for the exercise of the options In 2025.