Question:

On the auction 1NT-3NT, you are on lead with: 

Q974
43
K732
J87

What is your lead?

Answer:

4. While the fourth best from your longest and strongest is technically a diamond, the diamond and spade suits are roughly equivalent. When flipping a coin, remember that on this auction the dummy chose not to inquire about the majors. That means it's more likely dummy has minor-suit cards and it's slightly better to lead a major. If you had a five-card minor or a sequence in the minors, you would still lead those.