What exactly is a Flurry of Blows?

What part of attacks a monk makes during a full-attack routine constitutes a Flurry of Blows class-feature?

I was recently pointed out, Flurry of Blows says:

A monk must use a full attack action to strike with a flurry of blows.

This means, it isn’t necessary the whole full-attack, but maybe only some part of it. Should I elaborate, I always played monks with Flurry of Blows being the whole full-attack? Now, after some digging I see three possible cases, and I’m not sure which one is correct:

  1. I was right, and Flurry of Blows is a full-attack with some bonus attacks described by class-feature itself, as well as any other potential bonus attacks which all should qualify for Flurry of Blows restrictions.
    As a ‘backup’ for this version there is a table of a monk class calling attack bonuses of all attacks a monk makes using Flurry of Blows "Flurry of Blows Attack Bonus". Not "Attack Bonus When Using Flurry of Blows" or something similar. I think you got a point. Another ‘proof’ is a Fist of the Forest example statblock, which excludes bite attack from the whole routine (because it isn’t an unarmed strike or a monk weapon). Yes I know, statblocks are secondary. Still, better then nothing, I guess?
  2. Widly throuout the net it is assumed that Flurry of Blows is "An attack routine of a main hand with bonus attacks granted by class-feature itself". It isn’t restricted to a single hand, just to a number of attacks your BAB and FoB give you.
    Frankly, the ‘proof’ here is the same as above, just read differently – the table entry taken literally. To me it was obvious, they just taken the simpliest case to place into a table (attack routine with no other bonus attacks than those, given by the class-feature, table entry was describing). But at least some people claim that without a declaration of intent we can’t be sure what an intent was and we are left with what is actually printed in the table. Another ‘proofs’ are various FAQ entries, which expicitly allow natural attacks, for example, to be added after the Flurry of Blows in the same full-attack. I should point here, D&D 3.5 FAQ itself isn’t without issues, so should be emploued carefully.
  3. Flurry of Blows consists of only those bonus attacks class-feature itself gives you, and all other attacks in a full-attack a monk makes are just regular attacks.
    "Proof" here, as I understand, is a passage, quoted above in my question (while it may, probably, also support point two of it). FAQ rulings are also mentioned to support this point of view.

I’m interested, what interpreation is correct? Maybe, there is some completely different forth one, I have failed to notice?