Read the passage below and choose one correct answer for each question.

TET HOLIDAY CUSTOM

On Vietnamese New Year, people believe that the first person who visits their home during Tet holiday has a bearing on their welfare for the whole year. In contrast, the person who sweeps the floor on the first three days of this festive occasion might sweep away the wealth. The first day of Vietnamese Lunar New Year is reserved for the nuclear family, that is the husband's household. The second day of Tet is for visiting the wife's family and close friends. Same shops have opened and a few lottery stands are busy selling chances to people who feel lucky. Everyone is out on the street parading around in their new clothes. On the third day of Tet, the circle of connections becomes larger and is extended to the broader community outside the family by visits to teachers, bosses or a helpful person. On the fourth day, banks and shops reopen.  Transactions, although slower, will be conducted more cheerfully than usual. Offices open and work resumes.

Why do Vietnamese people avoid sweeping the floors on Tet days?