It would be A.
The attack will interrupt the pc's movement and push him a square. Then the pc can finish his move including continuing to close in on the ettin.
The ettin push ability is good for knocking one of the guys out of flanking so the group has to work a little to regain flank, or to knock someone into a flanked position with the ettin's allies. Or to wallop the guy into the big cooking fire the ettin is roasting the goat over. Remember a push does not have to be straight back, but can be back diagonally too. As long as the square is farther away then the origin square.
The attack will interrupt the pc's movement and push him a square. Then the pc can finish his move including continuing to close in on the ettin.
The ettin push ability is good for knocking one of the guys out of flanking so the group has to work a little to regain flank, or to knock someone into a flanked position with the ettin's allies. Or to wallop the guy into the big cooking fire the ettin is roasting the goat over. Remember a push does not have to be straight back, but can be back diagonally too. As long as the square is farther away then the origin square.