55 Greenwich is in Connecticut. However, there is another clue (probably 72) that refers to this question also. The answer for that clue is Chattanooga which is in Tennessee. Now Tennessee does fit your letter pattern. However I cannot pparse it
I had thought the state of Greenwich = Connecticut = CT
Switched = TC
On the radio = sounds like....but TC in my opinion does NOT sound like Tennessee!
These are thoughts only. I am not going to try and justify anything!