The correct answer is D. All the jobs people do are connected to other jobs.
If you are not sure about this, just use the system of elimination. A is incorrect because the division of labor doesn't refer only to construction jobs; B is incorrect because work can be split among more than two people; C is incorrect for the same reason as A - it doesn't have to be the medical field only. This leaves us with D as the correct answer - division of labor refers to jobs that are closely connected.
