To get into a levels at any sixth form or college you need a 4 (a C grade) or above in GCSE maths (ideally more than a 6 (a B grade) in most) and the same grade in GCSE english literature and english language. To do maths a level and do well, you should have at least a grade 7 (an A) in your maths GCSE. Business a level is not much like business GCSE, so you won't be at a disadvantage there. Try and choose a levels based off of the subjects you like - you like maths, and business pairs really well with maths - you can also use it to get into law, business or finance at university 🙂 If you like art or DT you should consider taking one of them to A level since you've already got 6/7 in your mock, but only if you really like it, as it is a lot of work particularly in art. If you like science or english, I would suggest taking the one you like most to a level, but if you do not then there is no point picking a subject you do not like to learn about.