My guess is that this is a typo and that the options should are
A are going to
B shall
C will
The best answer, as you correctly say, Sasha, is 'will'.
'are going to' is not the best answer because, as Morgan explains, this form usually indicates something pre-planned, so it isn't a prediction. That said, it is still possible. You can say 'I predict that .... is going to happen' in the sense that it seems inevitable.
'shall' is wrong. 'Shall' is only used with the second person ('you') when the speaker is being particularly insistent that something is the case, and is making a point of contradicting something previously said or believed. My favourite example of 'You shall....' is in the fairy tale Cinderella, when the fairy godmother waves her magic wand and exclaims 'You SHALL