Read the passage and choose the best answer.

Family life is changing. Two-parent households are on the decline in the United States as divorce, remarriage and cohabitation are on the rise. And families are smaller now, both due to the growth of single-parent households and the drop in fertility. Not only are Americans having fewer children, but the circumstances surrounding parenthood have changed. While in the early 1960s babies typically arrived within a marriage, today fully four-in-ten births occur to women who are single or living with a non-marital partner. At the same time that family structures have transformed, so has the role of mothers in the workplace – and in the home. As more moms have entered the labor force, more have become breadwinners – in many cases, primary breadwinners – in their families.

As a result of these changes, there is no longer one dominant family form in the US. Parents today are raising their children agianst a backdrop of increasingly diverse and, for many, constantly evolving family forms.

Which of the following trends is true in the United States?