How do I right a introduction about, "The Vikings were responsible for spreading civilization around Europe"?

From around A.D. 800 to the 11th century, a vast number of Scandinavians left their homelands to seek their fortunes elsewhere. These seafaring warriors–known collectively as Vikings or Norsemen (“Northmen”)–began by raiding coastal sites, especially undefended monasteries, in the British Isles. Over the next three centuries, they would leave their mark as pirates, raiders, traders and settlers on much of Britain and the European continent, as well as parts of modern-day Russia, Iceland, Greenland and Newfoundland.

Who Were the Vikings?

Contrary to some popular conceptions of the Vikings, they were not a “race” linked by ties of common ancestry or patriotism, and could not be defined by any particular sense of “Viking-ness.” Most of the Vikings whose activities are best known come from the areas now known as Denmark, Norway and Sweden, though there are mentions in historical records of Finnish, Estonian and Saami Vikings as well. Their common ground–and what made them different from the European peoples they confronted–was that they came from a foreign land, they were not “civilized” in the local understanding of the word and–most importantly–they were not Christian

d. china

good luck

d is the best choice

formulating the initial idea for the policy

answer is c.