naturalisation supporting docs

Hi

Can anyone tell me - when my wife applies for naturalisation, with regard to the 3 utility bills/bank statements, should she submit (a) the original supporting docs (b) photocopies of same or (c) photocopies of same that have been certified by the solicitor who witnesses our statuatory declaration?

The reason I'm asking is that she might need the originals for something else, very soon after lodging her naturalisation application, and if the answer is (a) above, we're anxious that Justice won't return the originals in time for her to lodge her application for the other thing...

We submitted copies and the only doc's that we had certified were the birth certs, marriage cert (husband likes to say he kept his maiden name) and the photo page of passports. All is well, as we are on for the 4th.