iMovie HD 6 and does it always interlace non-interlaced uploaded content

I'm using iMovie HD 6 to prepare a slide show from still photos (jpegs).

When you "Create a New Project" in iMovie HD 6, you get six choices:

DV
DV Widescreen
HDV 1080i (25 and 30 fps)
HDV 720p (25 and 30 fps)
MPEG 4 Simple Profile
iSight.

I want to create a slide show that will be shown on progressive screens and the slide show must be 854 X 480.

The iMovie setting of "DV Widescreen" produces a video/slide show of 854 X 480.

If I create a slide show using iMovie HD 6 with the "DV Widescreen" setting, and then export it to a high quality MPEG 4 file, will that MPEG 4 file be interlaced or will it be progressive?

I do not intend to export or share this with iDVD; I only intend to export the slide show to an MPEG 4 file.

Thanks!