Some people indulge in loud vulgar talk.

Answer: Option D

Vulgar : lacking sophistication or good taste.
Simple : easily understood or done; presenting no difficulty.
Restrained : characterized by reserve or moderation; unemotional or dispassionate.
Graceful : having or showing grace or elegance.
Refined : elegant and cultured in appearance, manner, or taste.

Antonym of Vulgar is Refined