Premise 1: From 1950 to 1975, the average number of students graduating per year at a group of five associated universities increased by 40 percent.
Premise 2: During the same period, the number of students graduating from these universities with honors degrees grew by only 20 percent.
Conclusion: None
Option A is the possible explanation for first premise, but it doesn't have to be true.; the criteria could have stayed the same (or become even less rigorous) while the students got worse.
Option B is again a possible explanation of the Premise 1, but it doesn't have to be true.
Option C is a possible explanation of the Premise 2, but it doesn't have to be true; the increase in enrolment (assuming enrolment - and not just the number of students graduating increased) could be due to the increase in the number of applications.
Option D is out of scope; we cannot establish a relation between honours degree (or no honours degree) with career orientation
So, we are left with E, E has to be it!
Pretty straightforward: Students graduating increased by 40%, but students graduating with honours increased by only 20%. Hence student without honours must increase more than 40% to balance two sides. Answer E.