Which conditions are caused by gastrointestinal infections?

B is the correct choice because gastrointestinal infections primarily manifest with symptoms that affect the digestive system. This includes nausea, vomiting, diarrhea, and abdominal cramps, which are typical responses of the body to an infectious agent affecting the gastrointestinal tract. These symptoms are the result of inflammation and irritation caused by pathogens such as bacteria, viruses, or parasites that invade the gastrointestinal lining.

Other conditions, while they may arise in response to infections or other health issues, do not directly correlate with gastrointestinal infections. For instance, shortness of breath is often associated with respiratory issues or other systemic conditions, joint pain and stiffness typically indicate musculoskeletal or autoimmune disorders, and fever and hypertension may appear in various infections or inflammatory responses but are not solely linked to gastrointestinal infections. Thus, the specific symptoms listed in the correct choice are the hallmark indicators of gastrointestinal infections.