Good news. You can't go wrong here! All applications will be treated equally regardless of what option you select. Stating a preference will not exclude you for being considered for the other role.
If your excel knowledge is limited, that's fine. If you can't tick the first box though, it may be a good idea to revise any claims of strong excel skills in your CV before submitting it!
Being greasy and saying Attacat will not help your application - honest!
We start our trainees on a low salary but ramp them up quickly as you prove yourself and your knowledge increases.
If you are just out uni with zero relevant experience we'll be looking at £16k unless you can persuade us otherwise. If you can bring other experience that is of use to us or are somehow truely exceptional then up to £20k may be on offer.
Seriously: This is probably the most critical part of your application.