Answer: b) Households increasingly include two primary income providers
Step-by-step explanation:
Demographic trend definition:
It refers to a major change in the characteristics and socio-economic factors that defines a particular population over time such as occupations ,marital status, education level,average family size and other socio-economic traits.
When there are two people who have income that will have an influence on their purchasing power because that increase the amount of money they make monthly.