B . Improvements in nutrition, sanitation, and health care cause death rates to fall in stage 2 of the demographic transition
Explanation:The epidemiologic transition occurs in medical geography and states that the changing population patterns in terms of fertility, life expectancy, and death can lead to causes of death. The second stage is viewed as the age of receding pandemics that states that due to the increase in medical aid and facilities. Morality progressively declines and the average life expectancy increases from 30 to 50 years.