Match each pioneer of epidemiology with his or her contribution.
â  nightingale
a. determined the source of a cholera outbreak in london
â  koch
b. showed that surgical wound infection rates could be dramatically reduced by using carbolic acid to disinfect surgical tools, bandages, and surgical sites
â  lister
c. compiled data on causes of mortality in soldiers, leading to innovations in military medical care
â  snow
d. developed a methodology for conclusively determining the etiology of disease