Mark and Maggie are married filing jointly and have four children (ages 12, 14, 16 and 18), all of whom qualify as their dependents. Mark and Maggie's tax liability before any tax credits is $5,800. They had $2,000 withheld as federal withholdings. In addition to their other children, they adopted a 2-year old special needs child this year. They spent $20,000on on the adoption expenses. What is the amount of their tax refund?

A. $5,600 refund

B. $7,600 refund

C. $18,780 refund

D. $24,700 refund

* Please explain and show work