What effect did Viking attacks have on Europe? (A) Europe was defeated by the Vikings, but managed to convert them to Christianity. (B) Europe signed treaties with the Vikings, sending them to North America. (C) The Vikings destroyed some European monasteries, but eventually rebuilt them. (D) The Vikings gained some land, but were eventually defeated by European forces.

(D) The Vikings gained some land, but were eventually defeated by European forces.

Explanation:

Vikings were very influential warriors in Europe and were feared because of their violent and bloody invasions across the continent. In fact, the Vikings conquered many lands, but were defeated in the battle of Edington in 878, in a battle against the army of King Alfred, at the same time the leader of the Vikings Guthrum converted to Christianity.

After that, looting and trespassing became less and less profitable causing the Vikings to ask for influence.

less available tax revenue

this basically means that when they get money from taxes wirth having a lower gdp they get less then what others have with a higher gdp