Once you've completed four years of college, you are no longer eligible for the AOC, even if you didn't claim it the whole four times while you were an undergrad.
So, generally grad students cannot claim the AOC, because they have completed four years of college. There is an exception. If you completed your undergrad degree early in 2024, then started grad school, you can claim the AOC in 2024 and even use the grad school tuition to calculate it. This is because you had not completed four years of post secondary education prior to 1-1-24.
