NO EXTENSION: Probably the least likely scenario at this stage as it would lead to an abrupt no-deal divorce on March 29 and the EU would not want to take any blame for the ensuing economic disruptions. But proponents of this route say Brexit has hijacked the EU's agenda and distracted the bloc from dealing with key challenges for too long and that the deepening acrimony should end now.

SHORT EXTENSION: An extension of up to eight weeks has so far emerged as the most likely scenario, with a firm deadline around the EU-wide parliamentary elections due May 24-26. European Commission head Jean-Claude Juncker said on Monday Britain needs to be out on May 23 at the latest, or else it would be under legal obligation to organise European Parliament elections on its soil. Britain does not want to do that and the bloc does not trust it would, potentially opening another legal row between the two. Few in the bloc, however, believe that a short delay would break the persistent deadlock in Britain, which reflects how the cabinet, parliament and nation are divided over Brexit. The bloc wants Britain to present a specific roadmap to approving the troubled divorce deal during any extension. But many diplomats and officials in the EU political hub Brussels admit the bloc would not really be in a position to refuse such a request and would grant a short delay regardless, albeit reluctantly.

LONG EXTENSION: A complicated option because it could open the way to legal challenges of the legitimacy of the European Parliament, or even the executive European Commission that the new chamber is due to pick by the end of the year, after May's European elections. But it is not entirely ruled out either. EU talk of a long extension - through the rest of this year or even until the end of 2020 - was in part aimed at putting pressure on the hardline eurosceptics in May's Conservative Party to back her deal, or risk Brexit potentially never materialising at all. Advocates within the EU say a long delay could open the way to a second referendum or a national election that could upend Brexit. Or it could give Britain time to change its mind on May's negotiating red lines and decide to seek a closer relationship with the EU after Brexit, such as the customs union proposed by the opposition Labour Party. It could also mean letting a contingent of eurosceptic UK lawmakers into the bloc's new parliament and potentially having them stay the whole, five-year term, giving them a say on EU affairs even after Britain might have left.