question: Q:A 40-year-old woman comes to the physician with a 5-day history of mild shortness of breath with exertion. She has also had a cough for 5 days that became productive of whitish non-bloody sputum 3 days ago. Initially, she had a runny nose, mild headaches, and diffuse muscle aches. She has not had fevers or chills. Three weeks ago, her 9-year-old son had a febrile illness with a cough and an exanthematous rash that resolved without treatment 1 week later. The patient has occasional migraine headaches. Her sister was diagnosed with antiphospholipid syndrome 12 years ago. The patient does not smoke; she drinks 3–4 glasses of wine per week. Her current medications include zolmitriptan as needed. Her temperature is 37.1°C (99°F), pulse is 84/min, respirations are 17/min, and blood pressure is 135/82 mm Hg. Scattered wheezes are heard at both lung bases. There are no rales. Egophony is negative. Which of the following is the most appropriate next step in management?? 
  {'A': 'Supportive treatment only', 'B': 'Obtain D-dimer', 'C': 'Perform Bordetella pertussis PCR', 'D': 'Conduct a high-resolution chest CT', 'E': 'Administer clarithromycin'},