kevin and karen are married taxpayers filing a joint tax return. in 2022, their agi is $320,000, and their net long-term capital gain income (included in the agi) is $90,000. they have investment interest expense of $4,000 and state and local income taxes attributable to the investment income of $6,000. what is the amount of medicare contribution tax that they must pay? a) $2,660 b) $3,420 c) $3,040 d) $2,280