The correct answer is option 4: All of the above. Bacterial diseases can affect plants, animals, and humans. In plants, bacterial diseases can cause various symptoms such as wilting, leaf spots, fruit rot, and can even lead to death of the plant. Some well-known bacterial diseases in plants include fire blight in apples and bacterial wilt in tomatoes. In animals, bacterial diseases are common and can affect both wild and domesticated animals. These diseases can cause a range of symptoms including respiratory issues, diarrhea, and skin infections. Examples of bacterial diseases in animals include anthrax, salmonellosis, and tuberculosis. Similarly, bacterial diseases can also affect humans, causing illnesses such as pneumonia, tuberculosis, strep throat, urinary tract infections, and food poisoning. Therefore, option 4 is the correct choice as it encompasses all the possible hosts of bacterial diseases.