Final answer:
The 11th-century "Great" Dane who united Denmark, England, and Norway was Knud the Great, also known as Canute.
Thus the corret opction is:a
Step-by-step explanation:
The 11th-century "Great" Dane who united Denmark, England, and Norway was Knud the Great.
Also known as Canute, he was a king of Denmark who eventually came to rule over England and Norway during the early 11th century.
His reign was noted for the consolidation of these Nordic kingdoms and his rule over the North Sea Empire.
This historical figure should not be confused with Erik the Red or Leif Erikson, who were famous Norse explorers, with the latter known for being one of the first Europeans to land in North America.
Similarly, William the Conqueror, despite being of Viking descent, was primarily associated with the Norman Conquest of England in 1066, well after the Viking Age.
Knud the Great stands apart as the ruler who at one point held sway over Denmark, England, and Norway simultaneously.