Here are two more. These are more difficult. Please give me your thoughts in the comments.
Exercise 5. West’s Lead against contract of 2NT by South:
You are West holding:
Bidding:
Usually you would like to lead a heart from that nice holding with an outside entry. But the opponents may very well have the ace and jack of hearts, so your entry may be driven out before the hearts set up. You would like to get your partner in to lead a heart. Would you consider leading your singleton club? It’s unusual to lead a singleton against NT. How about a diamond? Your opening lead and why?
Exercise 6. East’s Lead against contract of 1NT by North:
You are East holding:
