The period of adolescence is lengthening in industrialized cultures such as in Europe, the United States, and Australia. Adolescents are taking more time to finish their education and establish careers. The average age for a first marriage in the United States has increased more than five years since 1960, to for men and for women.

The average age for a first marriage in the United States has increased more than five years since 1960, to 28 for men and 26 for women.

Explanation:

The latest censuses carried out on the American population show that it has been common for men to marry at 28 years of age, while women marry at 26 years of age. This age has increased over time and especially in developed countries. This is because the concept of youth and adolescent in these countries has been extended. In these countries, young people take longer to reach adulthood and take responsibility for their own lives, as industrialization allows them to expect to have enough resources to enter adulthood once and for all and take on responsibilities such as marriage and children.

the answer is:

c. economic output