Final answer:
People who retire and then return to work in a different field typically have what is known as a second career. This term reflects a new professional phase separate from their past employment. Hence, the correct answer is option (1).
Step-by-step explanation:
People who get another job after being fully retired but work in a different field from the one in which they retired are said to have a second career. This term accurately reflects that they have embarked on a new professional chapter in their lives that is distinct from their earlier work. Other options such as a new profession, a different occupation, or a changed vocation could also be used, but a second career emphasizes the structured and committed nature of their post-retirement work.
The adult population is not merely divided into employed and unemployed, as there is a third group that includes retired individuals and those not actively seeking work, referred to as being out of the labor force. This includes people who are not working due to various reasons such as retirement, caregiving, or voluntary breaks, as well as those who have become discouraged after unsuccessfully seeking employment. Each situation has an impact on how economists understand and measure the workforce.