Explanation: Radio frequency (RF) waves are a form of electromagnetic radiation, just like visible light. All electromagnetic waves travel at the same velocity in free space (a vacuum), which is commonly known as the speed of light, often denoted as 'c'. Statement A provides a rounded approximation of this speed in meters per second. Statement B provides a more precise value in miles per second. Statement C directly states this fundamental principle. Since all three statements accurately describe the velocity of propagation for radio frequency waves in free space, "All of the above" is the correct choice.