Option C. The Normandy battle was important in making the Germans retreat to the East. This Operation was called Operation overlord which was implemented by the Allied forces. British, American and Canadian multitudes of soldiers who surreptitiously landed on the French coastline called Normandy formed to be the Allied forces.
Aggressive battle between the allied troops and Nazi militaries commanded by Hitler made the Germans to run back to their own country.
D-Day invasion is the other name of battle of Normandy.