Which of the Following Most Contributed to the Large Increase

Which of the following most contributed to the large increase in world population that occurred around the 1800s to 1900s?

A) Families increased the average number of children per household from one to three children.
B) Less women were dying in childbirth because they waited longer to have children.
C) The domestication of animals provided a larger food supply.
D) More people lived due to the discovery of vaccinations and medical treatments for deadly diseases.