根据短文内容，选择正确答案。
Vanuatu is an island nation in the South Pacific. It is one of the smallest countries in the world. But tor those who are interested in adventure and sport, there is a lot to do. Vanuatu's islands offer visitors two of the most exciting and dangerous activities in the world: volcano (火山) surfing and land diving.
Volcano Surfing
On Tanna Island, Mount Yasur rises 300 meters into the sky. Yasur is an active volcano, and it erupts (爆发) almost every day, sometimes several times a day. For centuries, people have climbed this mountain to visit the top. Recently, people have also started climbing Yasur to surf the volcano. In some ways, volcano surfing is like surfing in the sea, but in other ways it's very different. Volcano surfers try to escape the erupting volcano-without getting hit by flying rocks! It's last, fun and dangerous-the perfect extreme sport (极限运动).
Land Diving
Most people are familiar with bungee jumping, but do you know bungee jumping started on Pentecost Island in Vanuatu and is almost fifteen centuries old? The activity, first called land diving, is part of a religious ceremony (宗教仪式). A man ties tree vines(树藤) to his legs. He then jumps head-first from a high tower to touch the earth with the top of his head-without breaking the vine. Every spring, island natives (men only) still take Dart in this amazing activity.
st