Which of the following refers to symptoms related to infections of the lower respiratory tract?

The correct answer is related to symptoms that specifically affect the respiratory system, particularly in cases of infections in the lower respiratory tract, such as pneumonia or bronchitis. Symptoms that are associated with these infections typically include coughing, shortness of breath, wheezing, chest pain, and the production of phlegm or sputum. These respiratory symptoms indicate that there is an issue within the lungs or airways.

In contrast, cardiac symptoms would relate to the heart and may include chest pain, palpitations, or shortness of breath due to cardiac problems. Digestive symptoms involve issues in the gastrointestinal tract and may include nausea, vomiting, or diarrhea. Nervous symptoms pertain to the nervous system, potentially causing headaches, dizziness, or issues with coordination. Each of these categories deals with different systems in the body, underscoring why the symptoms from a lower respiratory tract infection are classified specifically as respiratory symptoms.