What did the soldiers take to prevent malaria?

The correct choice is Atabrine, which was specifically used to prevent and treat malaria during World War II. Atabrine is an anti-malarial drug that became a standard treatment and prophylactic measure for soldiers stationed in regions where malaria was prevalent. It helped to significantly reduce the incidence of malaria among troops, allowing them to remain healthy and capable of carrying out their missions.

Quinine, while effective in treating malaria, was primarily used in previous conflicts and was not the standard preventive measure at the time in question. Aspirin is used for pain relief and to reduce inflammation but does not address malaria. Penicillin is an antibiotic that treats bacterial infections and does not have an effect on malaria, which is caused by a parasite. Understanding these distinctions illustrates the importance of using the correct medication for specific diseases, particularly in a wartime context where maintaining soldiers' health was critical for operational effectiveness.