The government could of course put together a multi-choice referendum, or a two stage one. But they've no intention of doing so. And they'd need to get legislation to do it through parliament, which might be difficult.

I can see them going round in circles right up until the end of March. At that point, with No Deal imminent, given that there is so wide opposition to No Deal in the Commons, I can imagine a majority vote by MPs to cancel Article 50, and to hold a referendum to approve or overturn that, with Remain or No Deal Exit as the options.
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