CUSTOMS UNION: Several of the proposals advocate Britain remaining in the EU customs union -- likely after adopting May's withdrawal plan and its implementation period to the end of 2020. Committing fully to the customs union would end the dispute over her deal's provisions for the Irish border, ensuring it remains open after Brexit. This option is favoured by the main opposition Labour Party -- alongside close alignment to the EU single market -- as well as cross-party groups of MPs. But opponents argue it would hinder Britain's ability to strike trade deals with countries around the world, and the Conservative Party manifesto vowed Britain would leave the customs union.
NORWEGIAN MODEL: Although outside the EU, energy-rich Norway is in the European Economic Area (EEA) -- alongside Iceland and Liechtenstein -- meaning they benefit from membership of the single market but do not have a say in the making of its rules. They must also allow the free movement of goods, capital, services and people -- the EU's four freedoms -- with member states. However, they are not in the customs union. Its advantages are Britain's large services sector -- including the financial hub in the capital -- would be undisturbed. But critics say it would leave Britain hostage to EU rules, and also fall foul of the promise of the Brexit campaign to limit immigration.
SECOND REFERENDUM: Many Remain-backing MPs see a second referendum as the most viable path towards preventing Brexit, while others believe it could simply break the stalemate. Earlier in the month, a majority of MPs rejected postponing the Brexit date in order to hold another referendum.
CANCEL BREXIT: The most dramatic option would be to cancel Brexit altogether by revoking Article 50, the departure mechanism that set a two-year clock ticking down to March 29, Britain's original exit day. With two of the amendments urging this measure to avoid a no-deal departure, Bercow may give MPs the chance to vote on the option.
NO-DEAL: If no alternative course can be agreed, Britain will default to "third country" status with the EU as early as April 12, with trade relations run on World Trade Organization (WTO) rules. This involves tariffs and increased barriers that could disrupt the seamless supply chains that connect Britain and the EU. Lawmakers have already voted overwhelmingly to reject this option, meaning the speaker is doubtful to pick a new amendment again calling for it.