I'll perhaps work through the probabilities later but there are interesting features.
For example, Lho has some sort of decent values in diamonds. If he had the
AKx would he have started with the
K? The auction began 1 H -2
. He might worry that declarer can pitch a spade loser on clubs right away unless he takes his spades. If we decide that the lead makes it unlikely that Lho has
AKx then that makes it more likely that Rho does. Maybe not a lot more likely, but perhaps a 30% chance rather than a 25 % chance.
There is also the complicating feature that the
might fall in two rounds. Of course if it does, then line B will work just fine. Imagine for a moment it is matchpoints. Then, of the
Q falls on the second round of clubs, we can make an over-trick if hearts are no worse than 3-1. Go to the board in hearts, ruff a small club high, draw trump ending on the board, cash the
J and now the long
is also good.
Added: I thought of another way that line B could work. Suppose that the
AK brings down the Q and you lead a small heart to the board. Lho shows out. Rho has all four hearts. No problem. You lead the
J from dummy. Rho must ruff, otherwise that is a tenth trick. So he ruffs and you over-ruff. Now he ans dummy both have two hearts left. Lead a heart to dummy and lead a club, ruffing. There is now one club left in dummy, it good, a small heart to dummy draws the last trump, you cash the good club.
Here is an important point about mathematics that goes beyond bridge. Math is useful, very useful, it can allow you to draw conclusions from assumptions. But caution is needed. Often there is more to a situation than you at first think. Math can still be useful, it often is still useful, but there is a need for care.
All in all, it seems the recommended play of
AK is the winner.
Often purely abstract probability arguments have to be modified by inferences from the play. In this case I think the modifications enhance rather than detract form the argument for line B.