Kevin and Jill are married and file a joint return. Kevin is 52 and is not an active participant in a qualified employee pension plan, while Jill is 48 and is an active participant in a qualified employee pension plan. Determine the maximum Roth IRA contribution that can be made in each of the following cases:

a. Their adjusted gross income for the year is $122,000.

b. Their adjusted gross income for the year is $170,000.

c. Their adjusted gross income for the year is $177,000.

d. How would your answers to parts a and b change if Kevin makes the maximum allowable contribution to his deductible IRA?