Step 1: Identifying the role of Supreme Court judges.
The Supreme Court of India comprises appointed judges who hold office for life, based on merit and judicial expertise.
Step 2: Review of individuals.
Justice DY Chandrachud and Justice U U Lalit are both current Supreme Court judges.
Yashwant Vishnu Chandrachud was a former judge, but not a current one.
Harish Salve is a renowned senior advocate, but he has never served as a Supreme Court judge.
Step 3: Conclusion.
Thus, Harish Salve is not a Supreme Court judge, making option (4) correct.