Alex and Mary, both under 65, file a joint tax return for 2019. Their adjusted gross income is $55,100. This total included $4,000 of long-term capital gain from stock that has been held 3 years and 2 months prior to its sale in July. Alex and Mary claim the standard deduction. Their total income tax liability for 2019 is

Group of answer choices

$3,400

$3,600

$4,000

$4,200