From the auction I expect dummy to look like 3415 also eminently possible are 34-6,44-5,2416,24-7. As well as hands where dummy is holding 2♦ but I suspect I know where 11 of the ♦ are. So the underlead of the ♠A could be spectacularly successful or a dismal failure. The possible ♦ voids in dummy and partner holding ♦Kx could make an attempted passive lead in ♦ really dismal plus I think you need to make an aggressive lead so that rules out a ♥ or ♣ lead. I will probably guess the ♠A although if I need a swing I could try a small ♠