Marta has turned her attention to cultivating undergraduate students in the near future–three to five years from now. on which generation should she focus her attention?

The answer to this question is the Post-Millennials, because they are of the age that is just beginning to enroll in college.
Post-millenials generation tend to have a significantly different point of view compared to two generations before. This generation tend to seek more work-life balance and tend to more socially liberal compared to previous generations

Sector is best defined as (part).