Use human capital theory to explain how each of the following events will affect the likelihood that a person will go to college (provide a short argument that discusses which variable is affected):

(a) (5 points) a decrease in the earnings of high school graduates

(b) (5 points) a decrease in the years spent working after graduating

(c) (5 points) an increase in tuition

(d) (5 points) an increase in the person's discount rate