Final answer:
Yes, the children can be claimed as dependents because they were adopted before the end of the tax year.
Step-by-step explanation:
In this scenario, Tonya can claim the two children as dependents. The option c. Yes, the children were adopted before the end of the tax year is the correct choice.
To claim a child as a dependent, the child must meet several tests, including the relationship test, the age test, the residency test, and the support test. In this case, Tonya has fostered the children and then adopted them. Adoption establishes a legal relationship between the adoptive parent and the child, satisfying the relationship test. The age test is also met, as the children are 1 and 3 years old.
Furthermore, since the adoption was final on December 17, the children were in Tonya's home for more than half of the tax year, satisfying the residency test. Therefore, Tonya can claim the two children as dependents on her tax return.