Which one of the following persons would NOT be considered unemployed?

(a) A retiree actively looking for part-time work to supplement Social Security income

(B) A person who has moved to California from Michigan and is looking for a job

(C) A college student actively searching for a summer job and who is not attending summer school

(D) An auto worker vacationing in Florida during the layoff period, before the production of new models begins next month.