Answer:
Rush hour.
Explanation:
So, let us look at the meaning of the two words ''captive audience''. captive audience is simply a kind of audience in which compulsorily have to watch or listen to someone or something. This is an important aspect in which broadcasting use by dividing their daytime broadcasting periods into different dayparts.
Now that we know what captive audience mean, let us take a look at the question again. In the question, we have that, ''listeners are a captive audience in their cars...'' and why will that be? Simply because of traffic Congestion! And that is what is known as rush hour, that is the period of traffic Congestion and this may last for more than an hour.
