Christine and Doug are married. In 2020, Christine earns a salary of $250,000 and Doug earns a salary of $50,000. They have no other income and work for the same employers for all of 2020. How much 0.9 percent Medicare tax for high-income  taxpayers will Christine and Doug have to pay with their 2020 income tax return?
a. $450
b. $900
c. $2,700
d. None