Brendan and Theresa are married and have three children in college. Their twin daughters, Christine and Katlyn, are freshmen and attend the same univer-sity. Their son, Kevin, is a graduate student. Brendan and Theresa pay $12,000 in tuition and fees ($6,000 each) and $1,100 in textbooks ($500 and $600, respec-tively) for their daughters and $4,200 in tuition and fees for Kevin and $400 in textbooks. The twins room and board is $2,600, while Kevins room and board is $1,400. Brendan and Theresa have an adjusted gross income of $77,000. a. What amount can they claim as a tax credit for the higher education expenses they pay? b. Assume that their adjusted gross income is $121,000. What amount can they claim as a tax credit for the higher education expenses they pay? c. Assume the same facts as in part a, except that Kevin is a freshman and the twins are graduate students. What amount can Brendan and Theresa claim as a tax credit for the higher education expenses they pay?