**Core Concept**
Pneumomediastinum is a condition characterized by the presence of air or gas in the mediastinum, the central part of the chest cavity. It can result from various causes, including traumatic injuries, medical procedures, or spontaneous events. Management of pneumomediastinum involves stabilizing the patient and addressing the underlying cause.

**Why the Correct Answer is Right**
The management of pneumomediastinum often involves the administration of humidified oxygen to facilitate the absorption of air from the mediastinum into the bloodstream. This process helps to reduce the size of the pneumomediastinum and prevent further complications. In some cases, patients may also require close monitoring in the hospital or surgical intervention to address the underlying cause.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not address the specific management of pneumomediastinum.
**Option B:** This option is incorrect as it is not a standard treatment for pneumomediastinum.
**Option D:** This option is incorrect as it is not typically used in the management of pneumomediastinum.

**Clinical Pearl / High-Yield Fact**
Pneumomediastinum can be a complication of various medical procedures, including endoscopy and thoracentesis. It is essential to recognize the signs and symptoms of pneumomediastinum, such as chest pain and shortness of breath, to provide prompt and effective management.

**Correct Answer:** C. Humidified oxygen.