Second edit. Sorry, OP edited to show corret hands, and text edited to reflect the correct hands.
South decalrer. 24 board KO. Opponents silent. Your side bid to 6NT, not a good contract with 32 combined points, and 4333 distribution in both hands. Unfortunately only 9 top tricks. The ♦ will generate at least one trick, so you need two more tricks.
W leads a nondescript ♣. What is the best play to try to make 6NT?
Benefits include:
Plus... it's free!