Correct option is A
Meaning of the word "vulgar":
Crude, offensive, or lacking good taste.
Synonyms: crude, coarse, indecent.
Antonyms: refined, decorous, tasteful.
Meanings of options:
· Decorous – polite, restrained, and proper in conduct.
· Licentious – immoral, sexually unrestrained.
· Impervious – not affected by something.
· Ribald – referring to sexual matters in a rude or irreverent way.
Correct Answer: (a) decorous
"Vulgar" refers to offensive or crude language, and its antonym is decorous, which means proper and respectful.
Other options either reinforce the vulgarity or are irrelevant.
Example Sentence:
He always maintains a decorous tone in formal gatherings.