The source resolution is 720p. The display resolution is 1080p, no matter what the source (given that the image is stretched to fit the screen, of course).
So we're assuming the poll is talking about the display resolution, since very few games run in 1080p, so it would be dumb to have that option. Of course, this is a gamefaqs poll, so it's entirely possible that there are many dumb options, so I guess either interpretation would be fine.
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_foolmo_
mobile computer