for engineering :

if you say category than that doesn't matter for student of other student there won't be any reservation for you and if you are the domicile of west bengal than off-course the minority category,or the lower cast category will help you a lot to find good college in west bengal even if you your rank is no far better.

if by  category if you mean to ask about the branches in engineering college than i'll say that is your personal view that which branch you findmore attached to you and which subject you enjoy studing during your secondary school phase

even even if looking at placement cse is top branch off-course and than you may also go for information & technology and ECE

mechinical,electrical these are not so much good in wbjee by looking at it though placement.