**Core Concept**
Tension pneumothorax is a life-threatening condition where air enters the pleural space and accumulates under pressure, shifting mediastinal structures and compromising cardiovascular stability. The primary goal of treatment is to immediately relieve the pressure by decompressing the thoracic cavity.

**Why the Correct Answer is Right**
The best treatment for tension pneumothorax involves inserting a large-bore needle or a chest tube into the second intercostal space in the midclavicular line to allow air to escape and equalize pressure. This procedure is called needle decompression or chest tube insertion. The release of pressure helps to restore mediastinal shift, improve respiratory and cardiac function, and prevent further complications. The subsequent placement of a chest tube is crucial for continuous decompression and drainage of air and fluid.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not address the immediate need to decompress the thoracic cavity in a tension pneumothorax.
**Option B:** This option is incorrect as it does not take into account the urgent need for rapid decompression in a tension pneumothorax.
**Option C:** This option is incorrect as it is a more definitive treatment for a simple pneumothorax but not the immediate choice for tension pneumothorax.

**Clinical Pearl / High-Yield Fact**
In emergency situations, it's essential to remember the mnemonic "5 Ps" for tension pneumothorax: Pulsus paradoxus, Precordial dullness, Pneumothorax, Paradoxical breathing, and Pulsus paradoxus worsening with inspiration. This mnemonic helps identify the clinical signs and symptoms of tension pneumothorax.

**Correct Answer: C. Chest tube insertion.**