Obey : Defy :: Work : ?

The answer is A. Lazy.

Obey and defy are antonyms, meaning they have opposite meanings. Work and lazy are also antonyms. Obeying someone means doing what they say, while defying someone means doing the opposite of what they say. Working means being active and productive, while being lazy means being inactive and unproductive.

The other options are not correct because they do not have opposite meanings to work. Rest means to stop working and relax, idle means to be inactive, and labour means to work hard.