A. The answer is it depends.
C-corporation
With the new tax law passed in December 2017, C-corporations now pay a 21% flat rate. However, C corporation owners are still subject to "double taxation" - the corporation is taxed at 21% on its income and the shareholder/owner is taxed on qualified dividends at a top rate of 23.8%.
For high-bracket taxpayers, C-corporation may makes sense if they intend to reinvest the corporation's earnings back into the business, in this way, they will only pay the 21% flat rate.
Pass-through entity
For owners of pass-through entities, they now have the ability to take a 20% deduction on their personal income taxes for the qualified business income. However, owners still face a variety of definitions, limits, and phase-outs for the 20% deduction on qualified business income. The worst case scenario is a top income tax rate of 37% for pass-through business income.