The radio talk listeners
The reason why the "radio talk listeners" would be the correct answer is because this would be the "implied population".
The implied population is a group of people that's part of the "data".
In this case, the listeners are the one's that called the talk show host, due to the fact that they're listening in on the radio and hear what the talk show host told them to do.
They would be part of the "data" they the talk show host is collecting.
The data would be the 9 people that said yes, 6 people saying no, and 15 total callers.
All in all, the radio talk listeners are the implied population because they were the one's that are part of the "data" that the radio talk show host is collecting from the phone calls they received.
