(1) Vote for a deal (if not first time, then second time: maybe same deal or any variation/tweak)
(2) Persuade/"instruct" govt to seek extension/suspension of Article 50 (prob with EU consent)
(2) needs a reason/plan of what the agreed A50 extension is for: a referendum, or general election.
(Or another agreed delay, before choosing a withdrawal deal or a referendum. Ad infinitum, but only if by mutual consent)
Worth factoring in that Referendum (People's Vote) Bill probably the most contentious legislation of the last half century (much more than Maastricht).
It would more probably be a consequence of a General Election, not an alternative to one. (*If* GE led to change of govt & *if* that govt wanted a referendum & wanted to prioritise that).
(Which, even *if*accepted, just delays similar choice)
But they could.
And they probably would!
Labour's preferences are the inverse. Definitely (4) first, not sure if (3) or (2) next (leader, unlike party, not keen on either). (1) least favoured alternative.
If (4) & (3) fail, maybe (1)
1. Customs Union/EEA
3. SNP would vote for a general election.