Final answer:
Option (d), Mothers receive sole physical custody of their children approximately 80 percent of the time. The family structure has been evolving with a significant rise in single-parent households, though most U.S. children live in two-parent households.
Step-by-step explanation:
Today, mothers receive sole physical custody of their children approximately 80 percent of the time, so the correct answer to the question would be d) 80.
It is important to understand the changing dynamics of family structures in contemporary society. While there has been a notable rise in single-parent households, the majority of U.S. children still live in two-parent households.
However, this figure has been decreasing over the years, with significant declines in households headed by married couples. Whereas in 1960, 66 percent of households were headed by a married couple, this number dropped to 45 percent by 2010. This shift in family structures affects the living arrangements of children, with many now living in varied familial setups including with single parents and cohabiting parents.