xx
	xx
	Axxx
	AKxxx
	KJT9xxx
	x
	Kxx
	xx

East opens 4 and you bravely bid 4 ending the auction.  West leads a heart and East plays a second heart, you ruff while West completes a peter.  Which minor should you cross to dummy with to lead a Spade?

East is equally likely to be short in Clubs or Diamonds since you have seven of each.  It is correct to cross with a Diamond.  After you take the trump finesse and West wins, then if East can ruff a Diamond, having started with a singleton, East will be ruffing a loser.