Social Security and Medicare (HI) benefits are primarily financed by: a. A flat tax of 15% on corporate income. b. FICA taxes of 15%, 28% or 33% based on adjusted gross income. c. 6.2% payroll tax on earnings to $168,600 (2024) and 1.45% on all earnings, paid by employer and empolyee. d. A FICA tax of 1.45% up to $106,800