Greg and Casie are married and will file a joint return. For 2020, their modified adjusted gross income is $80,000. Their dependent daughter, Katelyn (21), is in her third year at State University. Greg and Casie are not students, and they have no other dependents. They paid $6,300 for Katelyn's tuition during the year. What is the maximum American Opportunity Tax Credit (AOTC) they may be eligible to receive