For 2019, Chanda is 36, single, and an active participant in a qualified employee pension plan. Determine the maximum Roth IRA contribution that she can make in each of the following cases:

a. Assume that she did not make any contributions to other IRA accounts during the year. When her adjusted gross income for the year is $66,000, Chanda is allowed to contribute $_6,000_ to her Roth IRA.

b. When her adjusted gross income for the year is $125,000, Chanda is allowed to contribute $______ to her Roth IRA.

c. When her adjusted gross income for the year is $139,000, Chanda is allowed to contribute $_0_ to her Roth IRA.

d. When her adjusted gross income for the year is $65,000, and she makes a $3,500 contribution to a deductible IRA account, Chanda is allowed to contribute $_2,500_ to her Roth IRA.