Janie graduates from high school in 2016 and enrolls in college in the fall. Her parents pay

Question:

Janie graduates from high school in 2016 and enrolls in college in the fall. Her parents pay $4,000 for her tuition and fees.
a. Assuming Janie's parents have AGI of $170,000, what is the American Opportunity tax credit they can claim for Janie?
b. Assuming Janie's parents have AGI of $75,000, what is the American Opportunity tax credit they can claim for Janie?