Which phrase provides the best clue to the meaning of impasse

こんにちは， 皆様、このサイトであまり日本語のpostを見つからなくて、もし質問があったら、ぜひcommentに聞いてください。 hello, i couldn't really find any posts on this site about japanese. but if you have any questions about japanese, feel free to ask me down below in the comments/replies. have fun learning !

Plagiarism—illegally using other people's ideas—can be avoided by a. adding a bibliography. b. proper documentation. c. taking good notes. d. using online sources only.

Kanother question for korean stuff it's for 38 points.