An 18-year-old man shot once in the left chest has a blood pressure of 80/50 mm. Hg, a heart rate of 130 beats per minute, and distended neck veins. Immediate treatment might include: A. Administration of one liter of Ringer's lactate solution. B. Subxiphoid pericardiotomy. C. Needle decompression of the left chest in the second intercostal space. D. Emergency thoracotomy to cross-clamp the aorta.