**Core Concept**
Cardiopulmonary resuscitation (CPR) is a life-saving intervention aimed at maintaining blood circulation and oxygenation to vital organs during cardiac arrest. Effective CPR involves a combination of chest compressions and rescue breaths to restore a viable circulation.

**Why the Correct Answer is Right**
The American Heart Association (AHA) guidelines recommend a compression-to-ventilation (CVR) ratio of 30:2 for adults in cardiac arrest, meaning 30 chest compressions are followed by two rescue breaths. This ratio is essential for maintaining adequate oxygenation and perfusion of vital organs. The compression depth should be at least 2 inches (5 cm) to ensure effective cardiac displacement.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not specify the correct ratio of chest compressions to rescue breaths, which is crucial for effective CPR.
**Option B:** The compression depth of 1 inch (2.5 cm) is insufficient to displace blood effectively in the chest.
**Option C:** The use of a compression-to-ventilation ratio of 15:2 is not recommended by the AHA guidelines for adults in cardiac arrest.

**Clinical Pearl / High-Yield Fact**
The key to successful CPR is the maintenance of a high-quality chest compression rate of 100-120 compressions per minute, while ensuring adequate ventilation.

**Correct Answer: C. The correct compression-to-ventilation ratio for adults in cardiac arrest is 30:2.**