I'm with Clara...it really depends on the purpose of the visit. If you are anonymously touring to see if you like the place, you will fit right in wearing either outfit. If you are meeting with faculty to interview for admission to a certain program or for a scholarship, please choose something that covers those bra straps!!!
I can't emphasize this enough. Visible bra straps are a cute, casual thing on anyone younger than mid-20s. But I'm going to guess that whatever faculty you may be meeting are closer to my age and most people my age do not get that look at all. If you are meeting faculty, consider it like a job interview...go slightly more formal than the atmosphere of the job so that you seem respectful and that you take the process seriously. So in this case, the skirt is perfect and age appropriate. Add a top that covers a bit more and looks just a touch more dressed and you will look like a college student who really wants to get that scholarship or study in that department.
If, on the other hand, you are going just take a student led tour to see if you even like the campus, either top is fine and you will fit right in.
