Walt and Deloris have two dependent children, Bill and Tiffany. Bill is a freshman at State University and Tiffany is working on her graduate degree. The couple paid qualified expenses of $3,900 for Bill (who is a half-time student) and $7,800 for Tiffany. What is the amount and type of education tax credits that Walt and Deloris can take, assuming they have no modified AGI limitation?