12th January, 23rd January, 5th September, and 14th November are celebrated as the Birth anniversaries of Swami Vivekananda, Subhas Chandra Bose, Dr. Sarvepalli Radhakrishnan, and Jawaharlal Nehru. Whereas, 30th January is celebrated as the Death anniversary of Mahatma Gandhi i.e Martyrs' Day. Hence, the correct answer is "30th January".