The correct answer is C. Dependency ratio.
The dependency ratio is a measure of the number of people who are dependent on the working-age population. It is calculated by dividing the number of people under the age of 15 and over the age of 64 by the number of people aged 15 to 64. A high dependency ratio indicates that there are a lot of people who are not working and need to be supported by the working population. This can put a strain on the economy and social services.
Sex ratio is the number of males per 100 females in a population. It is an important indicator of gender equality. A high sex ratio can indicate that there is a preference for male children, which can lead to female infanticide and gender discrimination.
Literacy rate is the percentage of the population aged 15 and above who can read and write. It is an important indicator of human development. A high literacy rate is associated with economic growth, social progress, and political stability.
Population density is the number of people per square kilometer. It is an important indicator of the impact of human activity on the environment. A high population density can lead to problems such as pollution, traffic congestion, and a shortage of resources.