The correct answer is option 4: Typhoid. Houseflies are known to be carriers of various pathogens, including those that cause diseases like typhoid. Typhoid fever is caused by the bacteria Salmonella Typhi, which can enter the body through contaminated food or water. Houseflies can pick up these bacteria when they come into contact with contaminated materials, such as feces or garbage, and then transfer them to surfaces or food items. When a person consumes food or water that has been contaminated by these bacteria, they can become infected with typhoid. It is important to maintain proper sanitation and hygiene practices to prevent the spread of diseases like typhoid that can be transmitted by houseflies.