The price paid for those contracts was roughly 15 cents. Although it might appear to be a lot of contracts, it isn't much money. Also, some of those calls might have been purchased by Pearson and friends as protection in case their short position blows up in their face. 15 or 20 cents is really a pretty cheap price to pay for insurance from a naked short position.
nitpicking here, but it doesn't make sense to say someone has a naked short position unless you're talking about a short-term intraday position. Naked shorting is when a stock is sold short without first locating shares to borrow for delivery. Unless you have an actual seat at the exchange, this is pretty much impossible to do. Even if you manage to do it, it is impossible to maintain this position over night since the clearing process will show an inevitable fail-to-deliver at settlement time and will shine a light on the fact that not only were the shares never borrowed, but they were never even located to begin with.