Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

While the western New Year is celebrated to some degree in Korea today, the traditional Korean or Lunar New Year, which usually falls at some point in early January or February, is still more important. The exact dates of the three-day celebration are determined by the phases of the moon and the beginning of festivities takes place on the first day of the second new moon. It isa very family-centred affair, which normally sees Koreans return to their hometowns to visit their parents and other relatives, and to perform an ancestral ritual called “charye”.

The first day is marked by a big meal. Family members usually dress in colorful traditional clothes known as Hanbok. The family-oriented theme continues throughout the festival, and a number of other customs are practiced during the three days, including the building and later, burning of moon houses which are made of firewood and branches. The destruction of the moon houses is a symbolic act intended to keep off evil spirits for the New Year.

The word “their" in paragraph 1 refers to _________.