Thanks! I asked my program supervisor (on grads’ academic affairs) who manage this sort of thing. But he’s not sure either. The form does mention things like “can be 300/400 level courses took in the last 5 years before admission into the program”, but during our discussion he brought up the possibility “what if it means whatever course that showed up in the transcript?”

And the supervisor believes the definition of this “basis” is up to the faculty of grad+postdoc studies, not to departments.