Final answer:
The correct manifestation of pertussis in an adolescent at an urgent care clinic would be identified as a dry, hacking cough.
Step-by-step explanation:
The nurse in an urgent care clinic should identify dry, hacking cough as a manifestation of pertussis, also known as whooping cough. Pertussis is caused by the bacterium Bordetella pertussis and is characterized by a prolonged period of severe coughing, during which a distinctive whooping sound may be heard when the person inhales after coughing. This cough is due to mucus accumulation in the lungs and inflammation of the airways. The catarrhal stage of pertussis includes symptoms like nasal congestion and a low-grade fever, but it is the paroxysmal stage, with its episodes of intense coughing, that is most associated with the classic symptoms of pertussis.