Studies show that obtaining higher levels of education is associated with
a. lower levels of unemployment, incarceration, and smoking
b. driving fuel-efficient cars
c. increased debt load
d. all of the answer choices are correct.

Higher education is associated with lover unemployment - so answer a) is correct.
However, in the US it's also associated with huge student debt- so answer c) is also correct. With higher wages and also higher knowledge people also more often choose fuel-efficient cars.  This makes the correct answer to be d)

The correct answer is a.f.c

It all depends on the individual