Final answer:
The nurse should respond therapeutically and empathetically when a client with ascites changes their mind about a paracentesis procedure.
Step-by-step explanation:
When a male client with ascites changes his mind and no longer wants the paracentesis procedure, the nurse should respond therapeutically by expressing empathy and understanding. The most therapeutic response would be option D: "Although the procedure is very important, I understand why you changed your mind." This response acknowledges the client's change of mind while still showing understanding of the procedure's importance.