Concept:Dependency ratio measures the number of dependents supported by every 100 working-age people.
Explanation:Dependents are people too young or too old to work, such as children and the elderly.
Working-age people are those considered productive, usually aged 15 to 64 years.
The dependency ratio compares the number of dependents to every 100 people in the productive age group.
Agricultural density, employment ratio, and population density do not measure this dependent-to-worker relationship.
Therefore, the correct answer is the option that directly expresses this measure.
Answer:B. dependency ratio