Which statement describes an impact of the collapse of the Western Roman Empire on Europe?

Which statement describes an impact of the collapse of the Western Roman Empire on Europe?
a. Europe’s economy improved significantly as new roads and infrastructure were developed.
b. Former Roman lands were split up and claimed by Germanic kingdoms.
c. There was a definite decline in Christianity, its followers, and its spread across lands.
d. Trade increased in the West, resulting in an end to the recession taking place at that time.