A draw is best tonight as it still keeps Chelsea busy looking over their shoulder but makes it less likely Liverpool make top 4. Plus neither win. It also takes top 4 out of Liverpool’s hands while it’s still possible.
If you hate Liverpool and think whatever happens Chelsea will still get 6 days rest and you really don't want Liverpool to have much chance at top 4 then go for United.
If you just want maximum pressure on Chelsea, even given the above, then go for Liverpool.
so for me...
1. Draw
2. United
3. Liverpool