North leads the Ace of trumps.
Which card should you play from Dummy ?

Before you make a rash decision on this, consider the number of possible losers there are : A♠, A♥, K♦ and K♣.
Four losers, and judging by North's Opening lead of a trump you will have little chance of ruffing Declarer's 3rd heart in Dummy. That makes 5 possible losers in total, two tricks too many.

The losers of the two Aces are unavoidable, but you can do something about Opponent's two Kings in the minor suits.
You must take two direct finesses in both ♦ and ♣. I will say no more !