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 $$461,600.$

His additional Medicare tax is $

$x.$

b$.$ George and Shirley are married and file a joint return. During the year, George earns wages of $$174,100,$ and Shirley earns wages of

$$261,150.$

Their additional Medicare tax is $

$x.$

c$.$ Simon has net investment income of $$56,040$ and MAGI of $$280,200$ and files as a single taxpayer.

Simon's additional Medicare tax is $

$x.$