Chatterjee is an executive with XYZ Corp. In 2015, XYZ gave Chatterjee 1,000 nonqualified stock options, each with an option price of $60, when the price of XYZ stock was $80. In 2016 Chatterjee exercised 500 of the stock options, at a time when the price of XYZ stock was $90. As a result of the above, what amount should Chatterjee include in 2016 gross income?
a. $0
b. $15,000
c. $10,000
d. $ 5,000