At Age 40,Joe Is Considering Quitting His Job and Going

Multiple Choice

At age 40,Joe is considering quitting his job and going back for a college degree.He needs two more years full-time.Tuition is $10,000 per year.He earns $30,000 per year.A college degree would raise his annual income by $10,000 per year.He will retire at age 70.If these are real amounts (adjusted for inflation) ,then the discount rate to be used should be

A) the nominal rate of interest.
B) the real rate of interest.
C) the rate of inflation.
D) zero.