He cannot decide to charge, because A interrupted B based up the fact that B ATTACKED. And if B attacked, then he can only continue with the attack, no more moves! (you need spring attack for this). The same happens in round 2. The key here is the ready trigger: when B attacks.
When B attacks, it means he has declared to attack (and he has already moved). Once he gets interrupted, he can't say, "no wait, i changed my mind, i no longer attack, i wanna first move another 5 ft". Because A's readied action has already happened BECAUSE he was attacking, an action that would not have happened otherwise.
Nope; as i see it, on the second turn, they start 5 ft away from each other. A readies again, and if B moves 5ft and attemps to attack... interrupt, readied action, A moves away 5 ft. B cannot say "no, i dont attack". He already said he would. So he actually attacks an empty square and then can move, but this accomplishes nothing.
B could maybe try to charge A, because you dont declare where you charge, just that you do. So, after he got interrupted, he could continue the charge "a little further"...except B needs 10 feet to charge, and he starts his turn only 5ft away from A, so charging is an illegal action for him in the first place.
Or B could ready on his own and try to outsmart A... but i really don't see an orc with 6 int trying to outsmart anyone. And this would mean every one on one is solely decided by intelligence... which i dont think it's true.
If B is an orc with 6 int but 15 class levels, he would get defeated by A, a little 5th level fighter, because the fifth level fighter is playing with the rules, and again, this isn't very credible at all.