Answer:
$2,500
Step-by-step explanation:
Elaine can deduct the first $2,000 and then [($4,000 - $2,000) x 25%] = $2,500 (maximum available deduction). Since Elaine files her taxes with her husband and their combined AGI is less than $160,000, then she can claim the full annual credit. The AOTC starts to phase out when the combined AGI is higher than $160,000 and phases out completed when it reaches $180,000.