Which best described most television in the 1940s and 1950s? color cable 24 hour black and white

The answer is "black and white".

Explanation:

During this period of live TV output in the United States, from the late 1940s to late 1950, the era between the 1940s and 1950s is often regarded as the first Golden Age of Television.  

It is the monochrome broadcast tv signal transmission and reception system. At the end of the 1940s, in 50 major cities, there were 98 commercial tv channels. TV sets costs also reduced by 1949.

8 track im pretty sure came first