【单选题】

One of the most significant elements of age stratification in all cultures is the pattern of experiences connected to marriage and parenting--a pattern that sociologists call the family life cycle. In NorthAmerica, about 90 percent of adults marry, and the great majority of them have children and thus a family life cycle related to family experiences. When the family’s first child is born, the parents embark on a sequence of experiences linked to the child’s development--from infancy and toddlerhood, through school age and adolescence, and eventually, to departure from the nest.Each of these periods in the child’s life makes a different set of demands on the parents.

The phrase embark on in the passage is closest in meaning to
A、ttempt
B．begin
C．iscuss
D．avoid