Hi, well this is the advice I can offer you, last year I picked ASs which I thought I'd do to keep my options open but it was tedious and I didn't enjoy it so I'm starting afresh, I'm doing history with only an a at gcse don't be put off by the work loud. For medicine you only need chem, bio is of litte use, I'd recommend chem history and maths A levels and u pick whatever for fourth as level, but that combo keeps options open for law medicine and business because it demonstrates variety and intellectual ability (ps my friends were suicidal doing 3 hours of maths a day) many have had to re sit cos of failing due to maths overload and they are very clever as it is a grammar school, so only take it if u enjoy it but further maths really is only of use for things like aeronautical engineering, hope this helped!