GG: thanks for yet another in a long series of great cases.
Key question: Who all, if anyone clearly heard A saying "two thousand" ? This is critical.
Further, there is implicit in the rules the idea that you have to "protect your action"... we see that expressly, for example, in the action-out-of-turn, significant-action, and accepted action regulations. As B put out five 1000's A had to be thinking to himself either: "B is raising" or "B mistook my bet of 2000". If he was thinking the latter, he didn't speak up.
Ditto, as C and E push out 5000, saying call, they are looking at B's clear bet of 5000... if they were thinking they are calling A's mumbled "two thousand" they sure didn't speak up.
Now we round the table and we can either:
1: Entertain a cascade of mistakes: A really bet 2000, and B only intended to call A but he thought A bet 5000, and C and E were piling on B's mistake...
OR
2: "Let the chips do the talking". The definitive action here is B's five 1000's. That can't be mistaken for anything other than a raise to 5K. A was silent so he didn't have a problem with it, C and E both "called" it...
My preferred ruling is just to call this 5000 total to A... he can fold, call (3000 more), or raise (to a minimum of 8k total).
How do you rule in this case?