Which of the following would the U.S. Bureau of Labor Statistics define as a discouraged worker?
a) Robert, a retired teacher, who works full time as a greeter at a discount store
b) Quinton, who has a doctorate in chemistry, but works full time as a taxi driver
c) Susan, who has been unemployed for the past three years and is looking for a part-time job
d) Mary, who was laid off last year and who was looking for a full-time job until last month