The correct option is D The adult population possess the knowledge, skills, and abilities required to produce various goods and services in a country.
The population of a country is divided into children, adults, and senior citizens. The adults come under the working population and form the workforce of a country. They possess the knowledge, skills, and abilities required to produce goods and services in a country. They are also employed as labour in agricultural, industrial, and service sectors. Therefore, the workforce of adults is directly connected to the nation's wealth and is considered as human capital.