What do you mean by 'Demographic Dividend'?

• A. A rise in the rate of economic growth due to a higher share of working age people in a population
• B. A rise in the rate of literacy due to development of educational institutions in different parts of the country
• C. A rise in the standard of living of the people due to the growth of alternative livelihood practices
• D. A rise in the gross employment ratio of a country due to government policies