The question asks about the disease that, according to the World Health Organization, causes the most deaths worldwide. Option 1, AIDS, although a severe global health issue, does not top the list. Option 3, Malaria, while widespread, especially in tropical regions, also does not claim the most lives. Option 4, Ebola, though highly fatal, isn`t as widespread, hence doesn`t cause the highest number of deaths. Option 2, Tuberculosis (TB), is correct. TB is a bacterial infection that primarily affects the lungs and is highly contagious. Despite the availability of potent treatment, a combination of factors including drug resistance, inadequate health care infrastructures, and co-infection with HIV makes TB the disease that currently causes the largest number of deaths worldwide.