You should make comprehensive use of your case studies. Therefore, it is most ideal to illustrate your points with case studies for both topics. Many students will only learn a case study for global. By using a case study for both topics not only are you better meeting the criteria, but you stand out from the average student.
'Sources of funds' isn't a great area of the syllabus to demonstrate your knowledge of a case study, but you could talk generally, as Deus pointed out.