If a lead looks like a singleton and smells like a singleton, assume it is a singleton. Furthermore, West figures to have both black aces to justify the opening bid. So if West has a singleton diamond, he is unlikely to also have a singleton ♣A. Apparently West has the ♣A J doubleton because he might have led the ♠A with the ♠A Q, and he might have doubled 5♣ with those cards.
Even though you apparently have three inescapable losers, hope springs eternal. Win the ♦A, cash the ♥A K, discarding a spade, ruff a heart, and make the big play — the ♣K.
Assuming the clubs are as you projected, and West has no more hearts, the best West can do is win the ♣A, cash the ♣J and lead the ♠A. It’s over! You ruff and cross to the ♦K to pitch your last diamond on the ♠K.
If instead of leading the ♣K you lead a lower club allowing East to win the queen, East can beat you several ways. East can return a diamond, driving out dummy’s only entry. This
allows West to safely exit with the ♠A when in with the ♠A. You ruff, but can’t get to dummy to use the ♠K and wind up losing a diamond.
East can also get out with a spade forcing you to ruff. Once again, West has a safe exit with the ♠A when in with the ♣A. What East can’t do is lead a heart. You ruff and now West is in big trouble. If West overruffs he has to lead the ♠A while the ♦K is still in the dummy. If West discards a spade, you gently throw him with the ♣A, again forcing the ♠A lead.