题目内容：
In the 1960s, many young Americans were dissatisfied with American society. They wanted to end the Vietnam War and to make all of the people in the U.S. equal. Some of them decided to "drop out" of American society and form their own societies . They formed utopian communities , which they called "communes," where they could follow their philosophy of "do your own thing." A group of artists founded a commune in southern Colorado called "Drop City." Following the ideas of philosopher and architect Buckminster Fuller they built domeshaped houses from pieces of old cars. Other groups, such as author Ken Kesey's Merry Pranksters, the followers fo San Francisco poet Steve Gakin, and a group that called itself the Hog Farm, lived in old school huses and traveled around the United States. The Hog Farm become famous when they helped organize the Woodstock Rock Festival in 1969. Steve Gaskin's followers tried to settle down on a farm in Tennessee, but they had to leave when some members of the gruop were arrested for growing marijuana.Not all communes believed in the philosophy of "do you own thing," however . Twin Oaks , a commune founded in Virgiania in the late 1960s, was based on the ideas of psychologist B.F.Skinner. The people who lived at Twin Oaks were carefully controlled by Skinner's "conditioning" techniques to do things that were good for the community. In 1972, Italian architect Paolo Soleri began to build Arcosanti, a utopian city Arizsona where 2500 people will live closely together in one large building called an "archology" Soleri believes that people must live closely together so that they will all become one.
What was the Twin Oaks commune base on ?
a.The philosophy of "do your own thing"
b.Virginaia in the late 1960s
c.The ideas of psychologist
d.The belief that people must live closely togerher.
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