Which of the following is a supporting detail of this paragraph?
Robots are being used in sumo wrestling contests. Sumo wrestling is a sport that started in Japan. It takes place in a ring. Two players try to score points by holding each other down or pushing each other out of the ring. Robot sumo uses robots instead of humans. The robot that scores the most points wins.
1. Robots are being used in sumo wrestling 2. Robots sumo contests are better than contests human sumo contests.
3. Robot sumo uses robots instead of humans.
4. Watching robot sumo is boring.