She bought a gaudy shawl as a wedding gift for her sister.

Answer: Option B

Gaudy : extravagantly bright or showy, typically so as to be tasteless.
Fatuous : silly and pointless.
Sober : serious, sensible, and solemn.
Garnish : decorate or embellish (something, especially food).
Ornate : elaborately or highly decorated.

Antonym of Gaudy is Sober