4.(20 marks) On December 31, 2018, in order to retain certain key executives, Entebbe Corporation granted them stock options. 25,000 options were granted at an option price of $ 40 per share. Market prices of the shares were as follows: December 31, 2019 $ 35 per share December 31, 2020 S 39 per share The options were granted as compensation for services to be rendered over a two-year period beginning January 1, 2019. The Black-Scholes option pricing model determined total compensation expense to be $ 500,000. Instructions a) Calculate the amount of compensation expense Entebbe to be recorded for calendar 2020. b) What if the vesting period were a three-year period? How would the financial reporting change