Where did the term Freemason come from?

The name dates back to the days when Freemasonry referred to those working in the trades. Numerous explanations have been suggested, such as: (a) Masons worked in free stone (which could be carved), and hence were called “free-stone masons,” later shortened to “freemasons;” (b) they were free men, not serfs; (c) they were free to move from place to place as they might desire; (d) they were given the freedom of the towns or localities in which they worked; (e) they were free of the rules and regulations that were usually imposed upon members of guilds.