Overall the project seems to be very well-made. Everything runs correctly as described in the original README. Any work I do on this legacy code project will probably center around either restructuring the class hierarchy present in the codebase or implementing new features to work together with the existing codebase.
Possible improvements:
Adjust design of the class hierarchy such that static members are minimized, resulting in cleaner dependencies between different objects. Add test cases to verify the functionality of the text parsing for the states as well as in many other portions of the code. Add new features to the project. For example, different kinds of quizzes, or maybe even quizzes for different countries.