Choose the option A, B, C or D to answer the following questions based on the information provided in the text. Then write the correct answer on the answer sheet.

People from different cultures have different space requirements. For example, South Americans and Middle Easterners stand closer when they talk or sit together than North Americans or Asians. In the United States, people need to have greater distances between them physically than people in many other cultures. Although Americans are often more affectionate and more likely to touch people they know, they have a great need for privacy, especially in the presence of strangers. For example, when Americans enter a bus, doctor’s office, or waiting room, they sit at least one chair away from the nearest person if possible. Conversation distance with superiors or those they don’t know well is about 3 to 4 feet. However, intimate conversations may be held as close as 1.5 feet apart. Because Americans feel uncomfortable if someone stands closer, they will naturally move away. Should this happen, don’t be offended. Your listener is merely stepping back to his or her normal conversational distance. (Adapted from “Cultures in the modern world”) 

How many main cultures are mentioned in the passage?