Pretty certain it is resident parent and resident step parent.
(It is one of life's mysteries (to me) that non resident parent income is considered irrelevant - not just for university funding but also child benefit. It's as if you can absolve yourself of financial responsibility for your child by leaving.)
Sorry about digression - you were asking a factual question! I'm fairly certain that is the answer, but others may confirm.
If you are divorced and remarried, whose income is relevant for applications for grants/fee reductions for university funding? a) mum (parent child lives with) b) dad (xh) c) step-dad (who child also lives with)