What does a flash mob refer to? O A. A group of people using the web to plan a time and place for participating in a seemingly spontaneous act B. Artists performing a creative piece in a theater that audiences have already bought tickets to see ting C. Two or three people working together to conceptualize, create, and install a public piece of art D. A group of friends exchanging original and wacky ideas on the Internet and deciding whose ideas are the craziest​