21

October 9, 1973

So the joke is that Brutus is listening to an old radio and what's playing is something that would've stopped being aired on the radio around 1950. "Old radio", get it?

It would be like you dug this out of your attic and all it played was
all the hit adult contemporary songs of 1985.

Surely Wilberforce knows how many consonants there are and he's just trying to trick Brutus. Just a fun little game that both Brutus and Wilberforce have lost.