<p>If you’re completely undecided just put undecided. If a major you selected fills up, they’ll probably offer you admission under your second choice. Switching isn’t too difficult for most majors. Just maintain a good GPA your first year, or maybe even just your first semester. Open options are for those who know the general area (science, business, etc) they want to study but not the specific major. They try a variety of classes for the first few semesters, then usually choose a specific major later down the road. I doubt you’d be at a disadvantage, but some open options are probably more selective than others, probably not by much though.</p>