Compute the additional Medicare tax for the following taxpayers. If required, round your answers to the nearest dollar.

a. Mario, who is single, earns wages of $516,600 in 2018. His total Medicare tax is $___________?

b. George and Shirley are married and file a joint return in 2018. During the year, George earns wages of $198,900, and Shirley earns wages of $298,350. Their total Medicare tax is $___________?

c. Simon has net investment income of $47,080 and MAGI of $235,400 and files as a single taxpayer. Simon's additional Medicare tax is $___________?