A. They were bound to the land and required to work there.
Explanation:
In manorialism, under feudalism, the workers were known as serfs. These serfs worked for a lord. They would sign a contract saying that they would work their land in order to live on it. However, this contract also stated that the serfs could not leave. This form of economy was extremely restricting for workers.
A concurrent power is a power that both the state and the federal governments share. The choice that is not a concurrent power is the power to sign treaties, because state governments cannot do so.