In $2023,$ Susan $(44$ years old$)$ is a highly successful architect and is covered by an employee$-$sponsored plan. Her husband, Dan $(47$ years old$),$ however, is a Ph$.$D$.$ student and unemployed. Compute the maximum deductible IRA contribution for each spouse in the following alternative situations.

Note: Leave no answers blank. Enter zero if applicable.

a$.$ Susan's salary and the couple's AGI before any IRA contribution deductions is $$224,000.$ The couple files a joint tax return. b$.$ Susan's salary and the couple's AGI before any IRA contribution deductions is $$140,000.$ The couple files a joint tax return. c$.$ Susan's salary and the couple's AGI before any IRA contribution deductions is $$85,000.$ The couple files a joint tax return. d$.$ Susan's salary and her AGI before the IRA contribution deduction is $$85,000.$ Dan reports $$5,000$ of AGI before the IRA contribution deduction $($earned income$).$ The couple files separate tax returns.