Examine the film’s soundtrack. What does the soundtrack tell us about the genre(s) used in the soundtrack?

I have been asked to do a research assignment. This assignment is to pick one of the movies provided by my university and it is to analyse the SOUNDTRACK’s GENRE of the film (not to analyse the film). This is for a Bachelor of Music major of a music university in Sydney, Australia.
I will attach a file of instructions and the criterias needed for this assignment. And also I will attach the essay guide style required from my university. There is also a list of the movie I have to pick to be analysed. It doesn’t really matter which movie you wanted to pick, whichever is the easiest for you. (just let me know which movie you’re going to choose before making the essay)
The movies are:
The Blues Brothers (1980)
Walk the Line (2005)
Crossroads (1986) (with Ralph Macchio, not the one with Britney Spears)
Oh Brother Where Art Thou (2000)
A Mighty Wind (2003) (this is a parody, so the answer will focus on the success or otherwise of the compositions within the context of parody)