Select the option that can substitute the highlighted word segment with the most appropriate idiom.
26 January 1950 is a memorable day for the countrymen.

Correct option is D

The correct idiomatic expression to substitute "a memorable day" is (d) "red letter day."
Red letter day: This idiom refers to a day that is pleasantly noteworthy or memorable. ( यादगार दिन)
Example: The day we won our independence is considered a red letter day in our country's history.
Meanings of the other given idioms:
· Green thumb - A natural talent or ability for growing plants successfully.
· Out of the blue - Something happening unexpectedly or without any warning.
· Black and white - Something that is clearly defined, with no ambiguity or room for interpretation; often refers to clear rules, decisions, or choices.