Step 1: Understanding the Concept:
The question asks to identify the case where an advocate's retention of a client's money was held to be professional misconduct. This falls under the advocate's duty of accountability and integrity towards their client. Misappropriation or wrongful retention of client funds is considered a grave form of professional misconduct.
Step 2: Detailed Explanation:
In the case of Prahlad Saran Gupta v. Bar Council of India, AIR 1997 SC 1338, the advocate had retained the money that was deposited with him for the decree-holder client even after the execution proceedings were over. He failed to return this money to the client despite repeated requests. The Supreme Court held that the advocate was guilty of gross professional misconduct. The act of wrongfully retaining the client's money is a breach of trust and brings disrepute to the legal profession.
- \textit{In Re DC Saxena} deals with contempt of court.
- \textit{Shambhu Ram Yadav v. Hanuman Das Khatry} deals with an advocate appearing for both sides.
- \textit{M Veerendra Rao v Tek Chand} also pertains to professional misconduct, but the specific instance of retaining decree money is famously associated with the Prahlad Saran Gupta case.
Step 3: Final Answer:
The correct case is Prahlad Saran Gupta v. Bar Council of India.