Excellent answer.Give that lady a cigar. Answer 1a is the closest to being correct. English was a polyglot language which assimilated much from the languages of foreign invaders over the centuries. The original gaelic of the Celts assimiliated latin from the Romans, the Germanic languages of the Anglo-Saxons, a nordic influence from the Danes and French from the Normans.

Before the unification of England under the Normans in 1066 AD, there were seven regional kingdoms (Essex, Wessex, Sussex, East Anglia, Northumbria, Mersia and Kent). They spent most of the time fighting with each other over dynastic or territorial disputes when they were not fighting off Viking invaders. By the 9th century Wessex had become the preeminant of the seven, and when Guthrum of Denmark invaded the other six kingdoms sought Alfred the Great of Wessex to lead an army of defense. Both the Danes and the regional kingdoms were strong enough to fight each other to a stalemate, but neither was strong enough to repel the other. Thereafter the English and the Danes entered into an uneasy truce. A portion of England was ceded to the Danes, and became known as Danelaw. Alfred set up a ring of fortresses on the border of Danelaw to contain Guthrum and his Vikings. The fortresses were known as Burgs or Burghs in the language of the time. Eventually settlements sprang up around the fortresses, and added the suffix Burg or Burgh to the name of the town signifying that it was a fortified city. 

Similar stories are also true of cities in other locations. Cities ending in the suffix "ford" usually were located on bodies of water or rivers.