Final answer:
The correct answer is A. Ignaz Semmelweis. He observed that mothers who gave birth in hospital wards staffed by physicians were more likely to suffer and die from puerperal fever after childbirth. Semmelweis proposed handwashing as a method to prevent disease transmission, which significantly reduced the mortality rate in mothers cared for by physicians.
Step-by-step explanation:
The correct answer is A. Ignaz Semmelweis.
In the 1840s, Hungarian obstetrician Ignaz Semmelweis observed that mothers who gave birth in hospital wards staffed by physicians and medical students were more likely to suffer and die from puerperal fever after childbirth than were mothers in wards staffed by midwives. He noticed that doctors often came directly from autopsies to the beds of women about to give birth, leading him to suspect that physicians were transferring the causative agent of puerperal fever to their patients. Semmelweis proposed that handwashing could prevent disease transmission, and when this practice was implemented, the mortality rate in mothers cared for by physicians significantly decreased.