How did the kings of
France increase their power?

William made tax collection more efficient, and required the first allegiance of all barons. Henry II claimed the right to try clergy in royal courts and unified the system of royal justice. ... Kings had to consult Parliament before levying taxes.

c. it required that townships set aside land for public schools.

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.