The correct answer is single flower.
A. small button
B. single flower
The correct answer is (B) Single flower worn in a lapel buttonhole; a flower worn on the lapel, or in the buttonhole of a lapel, usually by a man. Also, a small floral sprig or spray of flowers worn in a buttonhole.
Boutonniere comes from French boutonniere (buttonhole), Middle French bouton (button).
Examples of use:
- The prime minister always wore a boutonniere in the lapel of his suit.
- He usually selected a red rose for his boutonniere.