Option 1: A rise in the rate of economic growth due to a higher share of working age people in a population.

This option correctly defines the concept of `demographic dividend`. The term refers to a situation where a country`s population has a high proportion of working-age individuals compared to dependent age groups (children and elderly). This demographic advantage can lead to increased economic growth as the working-age population contributes actively to productive activities and generates income. With a larger workforce, there is a potential for increased productivity, innovation, and consumption, which can stimulate economic development and prosperity. This phenomenon is particularly relevant in developing countries that experience a demographic transition, where the population structure shifts towards a larger working-age population. It is important for policymakers to harness the potential of the demographic dividend by investing in education, skill development, and job creation to fully capitalize on the economic benefits.