In $2023,$ Juanita is married and files a joint tax return with her husband. What is her tentative minimum tax in each of the following alternative circumstances?

a$)$ Her AMT base is $$100,000,$ all ordinary income.

b$)$ Her AMT base is $$250,000,$ all ordinary income.

c$)$ Her AMT base is $$100,000,$ which includes $$10,000$ of qualified dividends.

d$)$ Her AMT base is $$250,000,$ which includes $$10,000$ of qualified dividends.