Poll: Who do you consider to be Manchester United's biggest rival?

Manchester United has 135 years of history as a football club*. A lot has happened during that time. Bitter rivalries have developed.

* They were founded, though, as Newton Heath LYR Football Club in 1878 and the club later changed it's name to Manchester United Football Club in 1902.

These are fluid times though. United have their long-time historical regional rivals like Liverpool and Leeds United. A contentious one with Arsenal arguably reached it's peak from 1997-2005 when the two clubs continually fought for supremacy in England. Roman Abramovich's ownership of Chelsea has changed the landscape in both English and European football and they became rivals to United in the latter half of noughties -- particularly after Jose Mourinho took the helm for awhile. 'Noisy neighbours' Manchester City have emerged in recent years backed by the riches of Sheikh Mansour.

Sunday is another meeting with Liverpool FC. We've discussed this topic here before in these parts but I'm curious to gauge where United supporters are at in regards to who is the club's biggest rival right now? Please vote in our poll and it would also be lovely if you shared your reasons in the comments section.