Can you please help with "B"?

Thank You

Niles and Marsha adopted an infant boy (a U.S. citizen). They paid $15,500 in 2020 for adoption-related expenses. The adoption was finalized in early 2021. Marsha received $4,000 of employer-provided adoption benefits. For part (a), assume that any adoption credit is not limited by modified AGI or by the amount of tax liability. Required: a. What amount of adoption credit, if any, can Niles and Marsha take in 2021? b. Using the information in part (a), assume that their modified AGI was $223,000 in 2021 . What amount of adoption credit is allowed in 2021? Note: Do not round intermediate calculations. Round your final answer to the nearest whole dollar amount