Trey has two dependents, his daughters, ages 14 and 17, at year-end. Trey files a joint return with his wife. What amount of child credit will Trey be able to claim for his daughters under each of the following alternative situations?
a. His AGI is $100,000.
b. His AGI is $420,000.
c. His AGI is $420,100, and his daughters are ages 10 and 12.