Which of the Following Is an Example of a Boomerang

Which of the following is an example of a boomerang child?

A) Greg, who is married with children, is moving back into his parents' home.
B) Mary is moving out of her parents' house because she has found a job.
C) Chris is paying his own tuition fees at college.
D) Harry, who is in high school, is working part-time to help out his parents financially.