Select the option that can be used as a one-word substitute for the given group of words.
An abbreviation formed from the initial letters of other words and pronounced as a word

Correct option is D

The correct one-word for the given group of words is (d) Acronym.
An acronym is an abbreviation formed from the initial letters of other words and is pronounced as a word. (शब्दों के पहले अक्षरों से बना और शब्द की तरह बोला जाने वाला संक्षिप्त रूप)
Example: NASA is an acronym for National Aeronautics and Space Administration.
Meanings of the given other options:
· (a) Caption: A title or brief explanation attached to an illustration or photograph. (शीर्षक, चित्र का विवरण)
· (b) Slogan: A short and striking phrase used in advertising or promotion. (नारा)
· (c) Flotilla: A small fleet of ships or boats. (नौकाओं का छोटा बेड़ा)