**Core Concept**
Tension pneumothorax is a life-threatening condition characterized by the accumulation of air in the pleural space, leading to increased intrathoracic pressure and compromised venous return. It requires immediate intervention to prevent cardiac arrest and death.

**Why the Correct Answer is Right**
The treatment of choice for tension pneumothorax is needle decompression, followed by chest tube insertion. This is because the rapid release of pressure in the pleural space is essential to restore venous return and prevent further complications. Needle decompression allows for the initial release of trapped air, thereby decompressing the thoracic cavity. Subsequent chest tube insertion facilitates continuous drainage of air and fluid from the pleural space, ensuring that the pressure gradient is maintained.

**Why Each Wrong Option is Incorrect**
* **Option A:** Chest X-ray is not a treatment option for tension pneumothorax, but rather a diagnostic tool to confirm the presence of the condition.
* **Option B:** Oxygen therapy is not sufficient to treat tension pneumothorax, as it fails to address the underlying issue of increased intrathoracic pressure.
* **Option D:** Surgical intervention is not the first line of treatment for tension pneumothorax, although it may be necessary in certain cases.

**Clinical Pearl / High-Yield Fact**
The classic clinical presentation of tension pneumothorax includes a sudden onset of dyspnea, hypotension, and tracheal deviation away from the affected side. The "mediastinal shift" sign on a chest X-ray is a diagnostic indicator of tension pneumothorax.

**Correct Answer: C. Needle decompression, followed by chest tube insertion.**