your UG matters most for your Stream.
However Marketing is the best stream for MBAs.
For other streams there are competitions with other Degrees also. But for Marketing less competition with other Degrees.
For Example. If you choose Finance then you will have competition with CA & CS guys also apart from MBA Finance students.
If you select HR, then there are less vacancies and more preference is given on Experience and also sometimes to female candidates.
If you select IT then you will face competition with B.Tech, M.Tech, & MCA guys too.
and believe me most of the things taught in MBA revolves round Marketing only. So I will recomend Marketing if you wish for MBA.