Choose the alternative which best expresses the meaning of the Idiom/Phrase.
26th January is a red-letter day in the history of India

Important day

The correct answer is OPTION 3 - Important day

The phrase "red-letter day" refers to a very important or significant day. In this context, 26th January, India's Republic Day, is marked as an important and memorable day in the nation's history. While it is also a historic day (Option D), the idiom "red-letter day" specifically conveys importance.