I recently did a science experiment on apple oxidation for school and here are the results of the apples are they've been left out overnight: http://imgur.com/a/1BhXoKT

So I have some questions, are the apples in lemon water doing the best? And how are the apples in milk doing better than vinegar as the milk shouldn't be affecting the rate of browning at all and the vinegar is slightly acidic? There also doesn't seem to be a difference between the apples in salt and lemon water and the apples without anything at all? 

Also, after some research about the brand of the apples, Pink Lady, I discovered they were high in acid so they were more resistant to browning, how does that affect my experiment besides it taking longer to turn brown? Thanks

Before you- or anyone- can say which apples are "doing better", you need to decide what you mean by "better".  That's part of the set up of the experiment.