Chati is giving a speech about food from Thailand, where he was born. His audiences consists of his classmates, most of whom grew up in the United States. He introduces the lecture by mentioning that one of the foods he misses most from Thailand is a fruit called durian. He says, "Many people from Southeast Asia, me included, call durian the king of fruits, both because of its large size and its delicious flavor. However, the sharp spikes covering its skin is not the reason why durian is banned from hotels and public transportation in some places." What is Chati's purpose with this introduction