Before 1860, most of the u. s. population lived and most workers . a. in small to medium cities; were members of trade guilds b. in rural areas; were self-employed c. in large cities; were self-employed d. in large cities; were employed in mills and factories

t

explanation:

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.