Generally speaking, if an operating budget is highly dependent on an endowment, then the endowment will have lower risk tolerance. That’s because if the endowment fails to provide capital, then the institution (that depends on the endowment) won’t have enough money to operate.
It is one of those questions where judgement is tested. As far as I know, Level III is a test of both knowledge and judgement.
I think this partially had to do with the fact that the endowments distribution went to 75% of funding the administration budget, and not necessairly the whole operation.
The question also states that donations are sufficient to cover shortfalls, which means that the foundations risk tolerance is not reduced despite the importance of its task.