under raising rule interesting question

[mosch]

This is explained in the excellent Robert's Rules of Poker.

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All raises must be equal to or greater than the size of the previous bet or raise on that betting round, except for an all-in wager. A player who has already checked or called may not subsequently raise an all-in bet that is less than the full size of the last bet or raise. (The half-the-size rule for reopening the betting is for limit poker only.)

Example: Player A bets $100 and Player B raises $100 more, making the total bet $200. If Player C goes all in for less than $300 total (not a full $100 raise), and Player A calls, then Player B has no option to raise again, because he wasn’t fully raised. (Player A could have raised, because Player B raised.)

[/ QUOTE ]

In the situation you described, player A can re-raise.