18. Adoption Credit. (Obj. 2) In 2019, a married couple paid $6,000 in qualified adoption expenses to adopt a child that is a U.S. citizen. In 2020, they paid an additional $4,200 in qualified adoption expenses. The adoption was finalized in 2020. a. Compute the couples' adoption credit if their modified AGI in both years is $115,000. In what year(s) is the credit taken? b. How would your answer to Part a. change if the couples' modified AGI was $224,800 in both years? c. How would your answer to Part a change if the couple adopted a child with special needs? d. How would your answer to Part a change if the adoption fell through