Why Do Teenage Mothers Experience a 'Double Transition' After the Birth

Why do teenage mothers experience a 'double transition' after the birth of their child?

A) they experience the double burden of being both mother and father to their child.
B) they experience the loss of their childless peers and loss of their ability to continue their education.
C) they experience the transition from school to home and the transition from childhood to adulthood.
D) they experience the transition to motherhood as well as the transition to becoming independent from their parents.
E) they will generally move from their parents home to a cohabitation arrangement with the father of the child.