Answer:
A. Culture
Step-by-step explanation:
Culture is very important and is reflective of how people communicate and etc. For example, the big business setting in China differs from America, so you would want to know how to be respectful of their culture. In China, when giving and receiving business cards, you have to accept it with two hands, not one hand. Failure to do so will cause you to look rude!
I hope this helps clear things up!