You are West on lead after this auction:
Here is your hand:
What card do you choose and why? Is it best to make an attacking lead or should you go passive and lie in wait with those nice diamonds? How many spades does declarer have? How many spades does partner have? Scroll down to read my recommendation.
I would go passive and lead a spade. You are unlikely to win a spade triick unless partner has the ace. Opponents have a 8-card fit in spades. Sit back with the KJ10 of diamonds behind the big hand. Your Q9 of hearts and even the 10 of clubs may be useful to your side on defense. Make declarer do all the work.