Michael is single and 35 years old. He is a participant in his employer's sponsored retirement plan. How much can Michael contribute to a Roth IRA in each of the following alternative situations? (Leave no answer blank. Enter zero if applicable.)

a. Michael's AGI is $58,000 after he contributed $3,900 to a tradition IRA. Contribution to Roth IRA?

b. Michael's AGI is $88,500 before any IRA contributions. Contribution to Roth IRA?

c. Michael's AGI is $143,500 before any IRA contributions. Contribution to Roth IRA?