You are answering a USMLE-style medical question. Question: A 46-year-old man is brought to the emergency department 15 minutes after being involved in a motor vehicle collision where he was the unrestrained driver. On arrival, he is unconscious. His respirations are 24/min, and palpable systolic blood pressure is 60 mm Hg, and pulse is 141/min and irregularly irregular. Examination shows multiple ecchymoses over the chest. There is a 3-cm (1.2-in) laceration over the abdomen and a 4-cm (1.6-in) laceration over the scalp. Jugular venous pressure is increased. Bilateral crackles are heard at the lung bases. Cardiac examination shows no murmurs, rubs, or gallops. The abdomen is soft. Two large bore intravenous catheters are inserted and 0.9% saline infusion is begun. Focused assessment with sonography in trauma (FAST) is negative. An electrocardiogram shows absent p-waves. After 5 minutes, his pulse is 160/min and palpable systolic blood pressure is 50 mm Hg. Vasopressors are administered. One hour later, the patient dies. Which of the following was the most likely diagnosis? Options: A) Cardiac contusion B) Hemothorax C) Aortic dissection D) Pulmonary contusion Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.