Why was feudalism developed? A. There was a need for a clear successor to the crown.
B. Centralized power was lost in the face of invasion.
C. The church was losing power and failed to protect the lords.
D. Lords decided to reform society by establishing chivalry.

I believe it is B

Explanation:

Because it is when the nobility held lands from the Crown in exchange for military service, and vassals were in turn tenants of the nobles and it would only really be needed in a time of war or an invasion.

the real answer is b

the reform movements that arose during the antebellum period in america focused on specific issues: temperance, abolishing imprisonment for debt, pacifism, antislavery, abolishing capital punishment, amelioration of prison conditions (with prison's purpose reconceived as rehabilitation rather than punishment), the humane treatment of animals, the humane and just treatment of native americans, the establishment of public institutions for the care of the destitute, orphans, blind, and mentally ill, the establishment of public schools, the abolition of tobacco use, vegetarianism, health reform, homeopathic medicine, woman's rights (including, at first, especially the establishment of a woman's right to own property apart from her husband and her right to sue for divorce), and the amelioration of labor conditions (including higher pay, the right to form unions, the right to strike, and the demand for limits on the number of work hours, and safe working conditions).

explanation: