A 67-year-old man with a history of stage IIIB lung cancer presents to the emergency department with acute onset dyspnea and hemoptysis. He underwent chemotherapy 2 weeks ago. Vital signs are: blood pressure 92/56 mmHg, heart rate 118/min, respiratory rate 28/min, and oxygen saturation 88% on room air. Physical examination reveals no lower extremity edema or calf tenderness. An electrocardiogram shows sinus tachycardia with new right axis deviation and an S1Q3T3 pattern. Troponin is elevated at 0.08 ng/mL (normal <0.04 ng/mL). Which of the following is the most appropriate next step in management?

1. A)Administer unfractionated heparin and obtain CT pulmonary angiographyGABARITO
2. B)Administer immediate thrombolysis followed by anticoagulation
3. C)Obtain chest X-ray and transthoracic echocardiography to assess right ventricular function
4. D)Perform serial troponin measurements and continuous cardiac monitoring
5. E)Order D-dimer testing to rule out pulmonary embolism