**Core Concept**
Pneumothorax is a life-threatening condition characterized by air entering the pleural space, leading to lung collapse and decreased lung volume. The clinical presentation of tachypnea, hypotension, and hyper-resonant note on the involved side is suggestive of a tension pneumothorax, an emergency that requires immediate intervention.

**Why the Correct Answer is Right**
In a tension pneumothorax, the accumulation of air in the pleural space leads to increased intrathoracic pressure, causing mediastinal shift and compression of major blood vessels. This results in hypotension, decreased venous return, and inadequate cardiac output. The hyper-resonant note on the involved side is due to the presence of air in the pleural space. The correct management of tension pneumothorax is the insertion of a chest tube to relieve the pressure and allow the lung to re-expand.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because inserting a central line in a patient with suspected tension pneumothorax would further compromise the patient's cardiovascular status.
**Option B:** This option is incorrect because administering oxygen in a patient with tension pneumothorax would not address the underlying issue of increased intrathoracic pressure.
**Option C:** This option is incorrect because performing a thoracocentesis in a patient with tension pneumothorax would not provide adequate decompression and may lead to further complications.

**Clinical Pearl / High-Yield Fact**
Tension pneumothorax should be suspected in any patient with chest trauma, hypotension, and decreased breath sounds on the involved side. A 'sucking sound' or 'scraping sound' heard on auscultation is a classic sign of tension pneumothorax.

**Correct Answer:** C. Insertion of a chest tube to relieve the pressure and allow the lung to re-expand.