Which term can be used to best describe the relationship between the underlined adjectives in “Unlike her gregarious sister， Jane is an unsociable person”？（）

Which term can be used to best describe the relationship between the underlined adjectives in “Unlike her gregarious sister， Jane is an unsociable person”？（）
A、Synonymy.
B、Antonymy.
C、Homonymy.
D、Polysemy.
正确答案：B