As many others have said Primary-Junior does not require a specialization like high school level. Here in Ontario the focus remains Math and Language in the school boards so having courses in those could be helpful.

What program is she trying to get into most teaching programs require a university degree before entering a teaching degree. If this is the case then she needs to think about what degree she plans to take. I took Psychology which is quite helpful in teaching elementary school. But, a degree in Art or anything can get you into the teaching program. I did find most students in my program came with random degrees and many quite very quickly because their degree was not related to teaching, they had no experience with children but rather had a random degree and no job lined up and many people suggested becoming a teacher to get their summer's off. They soon realized that yes the summers are off but the other 10months of the year are hard work and quit before finishing their degree.

If she is on a concurrent education program then she may need to have certain courses to aid in that.

I would choose a course that is of interest (higher grades) but is not a complete fluff course and something that can be built upon later (general math or language). In Ontario there are AQ courses (additional qualification) courses teacher take through the university's once you are a teacher that help teachers broaden their skills and become more 'hirable'. She can use those AQ courses to expand her 'arts' interests and it will help her move up in the pay scale and be attractive to certain principals. But, it's really a crap shoot...some principals want the artsy teachers some want strong math and language some what special needs etc. It's hard to know which basket to put your eggs into.