What is the most common impedance of coaxial cables used in amateur radio?

In amateur radio, almost all modern transceivers, antennas, and coaxial cables are designed to use a standard characteristic impedance of 50 ohms. This standardization makes it extremely easy to connect radios to feed lines and antennas without needing constant impedance matching or special adapters. The incorrect options represent common impedances found in entirely different electronic applications, not RF transmission lines. For example, 8 ohms is a standard impedance for audio speakers, and 600 ohms is frequently used in balanced audio lines or old-style open-wire feed lines. 12 ohms is simply an arbitrary distractor.