How can X1 visa be denied?

There are many probable reasons, like you don't have a firm financial background, your application documents are not sufficient, or the consular officer deems that you have the motive of immigration, etc. Anyway, just prepare well and you'll have good results.

Hi Michelle,
Well, Financial background will not be a problem. Moreover, I am going on a scholarship. My college will guide me through the process and take care of necessary documents. And since it's a two year course, and I'll have to move elsewhere at the end of it, I don't think immigration should be a problem either. Other than that, could there be an unexplainable reason or case for which the visa is denied?

There might be some unexplainable reasons, however, in normal cases, the consular officer will not make things difficult for you and you can get one.