when it says you need a C or higher for a class does that mean a C- would be too low?

Colleges & Universities Penn State
1

A lot of the entrance too major classes say that you need a C or higher for a class, does a C- mean that you need to retake the class?

2

There should be something listed in the grading policy for the university, and/or the major, which you can find at the website for the school to help you answer that. You want to know with a certainty to avoid a stress headache.

3

Penn State doesn’t generally have a C-.

http://handbook.psu.edu/content/grades-and-grade-point-average