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 $589,200 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 $205,100, and Shirley earns wages of $307,650. Their total Medicare tax is $______.

c. Simon has net investment income of $45,680 and MAGI of $228,400 and files as a single taxpayer. Simon's additional Medicare tax is $ _____.