The following devices are listed in which order: electro-optic devices, microwave RADAR, and VHF radio communications?

The correct answer revolves around the relationship between wavelength and frequency in the context of the devices listed: electro-optic devices, microwave RADAR, and VHF radio communications.

Electro-optic devices operate in the optical range of the electromagnetic spectrum, which corresponds to much shorter wavelengths (on the order of hundreds of nanometers). Microwave RADAR operates in the microwave range, typically at wavelengths measured in centimeters to millimeters, which are still relatively short compared to VHF (Very High Frequency) radio communications. VHF radio communications operate at frequencies around 30 MHz to 300 MHz, which correspond to much longer wavelengths—ranging from about 1 meter to 10 meters.

When the devices are ordered by their operational wavelengths, you move from the shortest wavelength of electro-optic devices to the longer wavelengths of microwave RADAR, and finally to VHF radio communications, which have the longest wavelengths among the three. Therefore, the sequence observed demonstrates a progression from shorter wavelengths to longer wavelengths, which makes the answer fitting.

In summary, identifying this relationship accurately leads to the conclusion that when arranged in order of wavelength, the devices transition from electro-optic (shortest) to microwave RADAR (medium) to VHF radio communications (longest