Hello,
The filling of seats in b category, depends on the students who apply for b category seats. If there are more people with rank below 100000, applying for b category seats at snist, it goes to them, else it is yours. We can't estimate what kind of people are going to apply in bcategory. The probablity of determining whether you can get a seat in b category can't be estimated. Hope you get it.
Thank You!