Answer :
The correct answer is D. The invasion and conqeust of England in A.D. 1066 by William, Duke of Normandy. Basically what happened was that Anglo-Saxons were getting cozy on the British isles having defeated and conquered the Celts and were getting complacent. Normans, who are something like ancient France, wanted to conquer them so they decided to cross the channel and in 1066 they managed to conquer them. This was an important turning point in British history.