Please, help me,

All of the following contribute to effective communication in groups excepta.)critical thinking.b.)understanding of subject matter.c.)individualism.d.)interpersonal communication skills.

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 !

What is the hardest language to learn?