Students have to attend all mandatory courses. Besides the modules A and B, compenstation within the module is possible in Bern as well as in Fribourg. Check the current study plans for each university for more details.
In addition to that, elective courses need to be taken to fill existing gaps. Students need to choose courses worth at least 10 ECTS. A list of possible elective courses can be found under "Legal basis / Anhang zum geltenden Studienplan". Students have the possibility to propose additional elective courses to the study administration.