An example of an unguided physical media:
3g technology
4g technology
local area radio channels
all of the above
none of the above

None of the above

Explanation:

 Unguided physical media is basically use in the transmission of the electromagnetic wave and it does not use any physical medium for transmission. It is also known as wireless transmission.

Physical media for transmission uses various types of cables for the transmission like twisted pair cable, fiber optics and coaxial cable. These cables are typically use within the various types of building for transmission.

Therefore, unguided media does not use any type of physical media for the transmission so the answer is none of these.  

answerparameter;

the answer to your question would be something called hertz. the unit of measurement called a hertz, which is one cycle per second, is used to measure clock speed. within one cycle, your computer processes, refreshes, or updates itself to the changes that it is going through. in the case of computer clock speed, one hertz equals one tick per second. the clock speed of computers is usually measured in megahertz (mhz) or gigahertz (ghz)