Which of the following is themostcommonly used demographic tool for examining fertility,mortality, and migration in the studyofpopulation?A. Dependency ratioB. Mortality chatC. PopulationcensusD. Population pyramid

The most commonly used demographic tool for examining fertility, mortality, and migration in the study of population is D. Population pyramid.

A population pyramid, also known as an age-sex pyramid, is a graphical illustration that shows the distribution of various age groups in a population, which forms the shape of a pyramid when the population is growing. It is commonly used in demographic research, economics, social sciences, and in ecology for studying the population of a country, city, or other geographic region.

Population pyramids can provide information about the age and sex structure of the population, as well as important information about certain demographic phenomena such as birth rates, death rates, and migration patterns.

Therefore, while all the options provided are tools used in demographic studies, the population pyramid is the most comprehensive and commonly used tool for examining fertility, mortality, and migration.