Lionel is an unmarried law student at State University Law School, a qualified educational institution. This year Lionel borrowed $24,000 from County Bank and paid interest of $1,440. Lionel used the loan proceeds to pay his law school tuition. Calculate the amounts Lionel can deduct for higher education expenses and interest on higher education loans under the following circumstances:

a. Lionel's AGI before deducting interest on higher education loans is $50,000.

b. Lionel's AGI before deducting interest on higher education loans is $74,000.

c. Lionel's AGI before deducting interest on higher education loans is $90,000.