The correct answer is option 2, Cinchona tree. Malaria is a potentially life-threatening disease caused by parasites transmitted to humans through mosquito bites. The drug extracted from the Cinchona tree, specifically the bark, is called quinine. Quinine has been used for centuries as a treatment for malaria due to its antimalarial properties. It works by attacking the parasites in the bloodstream and preventing them from multiplying. Quinine has been highly effective in treating malaria and has saved many lives. It is also commonly used today as a component in combination therapy for the treatment of malaria. Other options mentioned in the question, such as Belladonna tree, Oak tree, and Neem tree, do not contain the specific compound needed to effectively treat malaria.