Read the following article and select the best answer. Article: This August, we'll welcome guests from all over the world. Some of them follow their own special cultural traditions. It's important for us to know about them. *In many countries, such as Thailand, India and Malaysia, people believe that the left hand is unclean. So, it's not proper to use one's left hand to hold food, touch others or pass objects, Doing so may _ certain guests. *Some Westerners may be offended if you touch them or their personal things-even by accident. If this happens, say sorry politely. *Some elderly Westerners may be offended if you try to help them without their agreement. *People think numbers can be lucky or unlucky. Some Westerners avoid the number 13 because they believe it is unlucky. *Muslims do not eat pork, and words like pigs are not considered proper. *People from Brazil, Italy and Pakistan do not give handkerchiefs as gifts. They believe a handkerchief is closely connected with unhappy feelings. *Wine is not sent as a gift in many parts of western and middle Asia, where most Muslims live. Question: What does the passage mainly talk about? - Lucky numbers. - Traditional food. - Culture differences. - Hands and handkerchiefs.
Answer:
Culture differences.