This applies to a work that contains a collection of CC licensed works.
For more information and examples of this type of work, check the segment on collections under 'Reusing CC works '.
What CC license can you apply to a collection:
Any of the 6 CC licenses
The license you apply only applies to your own creative additions; the works the collection contains all regain their own CC licenses. Therefore, any of the 6 CC licenses could be applied to the collection. Which license you should choose depends on if your institution has a prescribed license. If not, consider the kind of (re)use you want to permit. Under ‘What is Creative Commons’ you can check out each of the licenses and their conditions.
Your institution's prescribed license
Institutions may prescribe a specific licence. Rotterdam University of Applied Sciences publication policy advises a CC BY license for publishing research. There is currently no policy that applies to educational resources, though CC BY is also commonly advised for this as well.