Scholarship/funding based on publications/research work
In general, while universities will look for publications, they won't entirely compensate for poor transcripts. Also, there is no "ideal" number of publications here: the more, the better. 

With a C+ average, though, you are unlikely to get a scholarship in the US. I should also point out that in central Europe, master's studies don't normally have tuition, and so scholarships aren't normally awarded: you instead need to get funds to support your living expenses.