A level choicesWatch
(also, definitely take maths!)
(Be warned that the page is slightly out of date and I would suggest double checking on all the universites' websites).
For your fourth it honestly does not matter. It's a misconception that universities prioritise students that have done specific A level combinations; as long as you take the required subjects and your third A level is an academic subject (i.e. not general studies or critical thinking), then you're good! I would suggest picking a subject that you're interested in, that you enjoy, and that you think you'll get a good grade in. I personally did physics as my third (and maths as my fourth AS) but I know other people at vet school who took geography, history, French, English literature, sociology, psychology and PE.
From your suggested options, I would potentially avoid food nutrition and health and social care, but the others are fine
Bio, chem, physics and maths (AS) is what I did and I found the workload manageable. It was definitely less work than some of my friends who took more essay-based subjects.