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? Use Exhibit 8-8.

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.