单项选择题

In the USA square dancing has been the most popular style of folk dance for quite a long time. In early days, people danced happily with each other once their farm work was finished. At that time music mainly originated from the violin. However, people used clapping to produce the rhythm if there was no one who could play a musical instrument. Settlers danced in a kitchen, a store, or on a farm.
Four couples are needed to form a square, all of whom stand in face of the center of the square. Every couple stand on one side of the square, the man on the left and the woman right.
The caller plays an important role in the dance, because he needs to tell the dancers which steps they should take. He will teach the dancers steps if they don’t know. Becoming a good caller takes much time. No doubt good callers are in demand forever.
Following are the names of some common steps: Form a square; Circle; Honor your partner; Swing your partner; Form a star. Just name these. When the callers tell the dancers what to do next, they move to form the pattern he orders.
People, be it many or few, can dance at the same time. You can see up to 1, 000 people dancing at one time. Sometimes only eight people of a square are dancing.
People who do square dance wear special clothes, which makes dance even more pleasant to watch. One place’s special clothes vary greatly from other places’. Women always wear skirts of various colors with a wonderful blouse, while men are dressed in shirts and trousers which they wear only when they do square dance.
Nowadays in the US you can still find some schools, clubs, or groups that are square dancing for great fun.

From this passage we know square dancing stems from()

A. the stores
B. the countryside
C. the schools
D. large cities