Step 1: Identify the appointed Chairman.
The correct answer is Justice V. Ramasubramaniam, who was appointed as the Chairman of the National Human Rights Commission in December 2024.
Step 2: Verification of other options.
Justice Madan Bhimarao Lokur, Justice Dhananjaya Yeshwant Chandrachud, and Justice Ranjan Gogoi are notable judicial figures, but they were not appointed as the Chairman of the NHRC for the given period.
Step 3: Conclusion.
Based on the information, Justice V. Ramasubramaniam is the correct answer.