Final answer:
The correct compression to ventilation ratio for a single rescuer providing CPR to an adult is 30 compressions to 2 ventilations, which ensures proper circulation and oxygenation.
Step-by-step explanation:
The compression to ventilation ratio for a single rescuer giving CPR to an adult is 30 compressions to 2 ventilations, which is option b, 30:2. This ratio is recommended by the American Heart Association to ensure proper circulation and oxygenation during cardiac arrest. It's important to perform these actions with minimal interruptions to maximize the chances of survival. The rescuer should aim to perform compressions at a rate of 100 to 120 per minute and to a depth of at least 2 inches (5 cm).