Question

What was the reason for Viking invasions?

A The land was desirable.
B The Vikings wanted to destroy Christianity
C There was a lack of strong rulers.

Answer 1

lack of strong rulers ;)

Answer 2

A The land was desirable.
Reason
Because on the Viking Age, which archaeological discoveries and written texts suggested lasted from about A.D. 750 to 1050, ship borne crews from Scandinavia went "viking" — that is, they started raiding. However, the causes of these invasions remain uncertain.

Hoped this helped :D