Answer:
The answer is D.
Explanation:
Labor force is the number of people or citizens who are within the workforce age that employed and those that are unemployed but are willing and able to work(i.e they are actively searching).
Labor force = employed citizens plus unemployed citizens
Option A and B are wrong because some adults(citizens) are not working and they are not willing to work.
The most important thing here is to show willingness to work and also has the ability to work