What is a socially constructed concept?
A. An idea that is not necessarily true or scientifically proven, but is developed by people
B. The fight to end the institution of slavery in America
C. A contract to work for a certain number of years in exchange for transportation
D. A form of slavery in which slaves are considered property

A. An idea that is not necessarily true or scientifically proven, but is developed by people.

Explanation:

It is a concept created by society, something created by social use or customs. For example, the notion of "race" is a socially constructed concept. Race is not really a scientific fact, but we use it and we give content to it by our social use in a context.

a.

congress passed laws allowing for free passage between states.