In 2017, Elaine paid $2,240 of tuition and $940 for books for her dependent son to attend State University this past fall as a freshman. Elaine files a joint return with her husband. What is the maximum American opportunity credit that Elaine can claim for the tuition payment and books in each of the following alternative situations? (Round your intermediate calculations to two decimal places and final answer to the nearest whole dollar amount. Leave no answer blank. Enter zero if applicable.)

a. Elaines AGI is $100,250.

b. Elaines AGI is $163,500.

c. Elaines AGI is $185,500.