What if, instead of being one of the people we've already gone over, it was in fact the real answer was E - all of the above? One of the wilder ideas as to The Ripper's identity isn't that he or she was someone, but that the murderers were committed by multiple people. It's a legit conspiracy theory, as a group of people conspired to kill a bunch of people and they got away with it! Kind of like the Neighbourhood Watch Alliance, this idea supposedly explains why nobody ever got arrested (because each murder was done by a different person, making the pieces impossible to put together), why reports of The Ripper are so dissimilar, and why the various notes he sent to the police looked to be written by different hands. Author Stephen Knight who - yes - wrote a book called Jack the Ripper: The Final Solution, argued that the murders were a conspiracy involving multiple repeat offenders, but there are still others who think that the whole thing is just some absurdist joke. According to Peter Turnbull there's a very real chance that each murder was committed by unconnected individuals, acting completely independent of each other, and it just so happened that each of their modus operandi and killing styles perfectly matched up. In which case, Jack The Ripper wasn't a serial killer, but just a bunch of people doing one bad murder each. Which is, like, the darkest joke we've ever heard.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/