Why Is the Battle of Hastings (1066) Referred to as One

Why is the battle of Hastings (1066) referred to as one of history's rare decisive battles?

A) Harold, earl of Wessex, and his Anglo-Saxon army succeeded in wiping out the army of the Norman invader, William, in a single day.
B) Lord Hastings led his Anglo-Saxon army into a trap laid by William, duke of Normandy, resulting in the army's total encirclement and its immediate surrender.
C) William and his army of Norman soldiers so decimated the Anglo-Saxon army, killing its leader, King Harold, that they were able to overtake England unopposed.
D) Both contenders to the English throne-the duke of Normandy and the earl of Wessex-were killed, opening the way to a successful invasion by Harald Hardrada, the king of Norway.