Donald Trump has made a video asking Obama to release his college records, applications and passport information, saying that in return he will give $5m to a charity of Obama's choice. There has been widespread and fervid speculation that Obama will probably ignore the request.

But why $5m? Is a particularly good rate for college application information these days? Or is it just the current "offer one can't refuse"? Who decides these things? It's hard to say at this point: all we can be sure of is that before making the video Trump and his assistants had a conversation almost exactly like this one: