Travelling around the world with children is difficult enough, but attempting it without using motorized transport is even more of challenge. But Dario Schworer, a 42-year-old climatologist and mountain guide, and his 33-year-old wife Sabine are on a journey to do just that. The Swiss couple want to travel across the world's oceans and climb the highest mountain on every continent to promote Earth-friendly ways of life. "We are collecting good examples of dealing with climate change and living in harmony with nature and we want to spread such ideas," Schworer said. "We want to help people affected by global warming and to inspire children for the future." Recently after having spent three months teaching children in the Everest region, the couple want to show it is possible to travel through as the world's climate zones using just human-power and forces of nature. In the 47 countries they have visited so far they have collected 22 tons of trash, taught people in Ecuador how the sun's rays can be used to clean water and inspired a person in Chile to build a house on water with recycled plastic bottles as a foundation. They have also collected trash in the mountains of Nepal with school children. So far they have communicated with 45,000 children from South America, Australia and Asia, giving presentations about the importance of recycling and using alternative energy like solar and wind power. "We need to motivate children," said Sabine. When they began their adventure in 2003 they had no children of their own. But since then two has become five: daughter Sabine is now five years old, Andri was born in Chile and baby Noe was born in Australia.  _ the couple thought they would complete their travels in four years, but now, seven years later, they believe it could take seven more. "Since our belief is the need to respect nature, we travel only when conditions are good," Schworer said. The best title of the passage can be   _  .
A Swiss family' journey across the world An eco-friendly adventure across the world We have a long way to make a good travel Nature needs respecting and protecting
Question: Travelling around the world with children is difficult enough, but attempting it without using motorized transport is even more of challenge. But Dario Schworer, a 42-year-old climatologist and mountain guide, and his 33-year-old wife Sabine are on a journey to do just that. The Swiss couple want to travel across the world's oceans and climb the highest mountain on every continent to promote Earth-friendly ways of life. "We are collecting good examples of dealing with climate change and living in harmony with nature and we want to spread such ideas," Schworer said. "We want to help people affected by global warming and to inspire children for the future." Recently after having spent three months teaching children in the Everest region, the couple want to show it is possible to travel through as the world's climate zones using just human-power and forces of nature. In the 47 countries they have visited so far they have collected 22 tons of trash, taught people in Ecuador how the sun's rays can be used to clean water and inspired a person in Chile to build a house on water with recycled plastic bottles as a foundation. They have also collected trash in the mountains of Nepal with school children. So far they have communicated with 45,000 children from South America, Australia and Asia, giving presentations about the importance of recycling and using alternative energy like solar and wind power. "We need to motivate children," said Sabine. When they began their adventure in 2003 they had no children of their own. But since then two has become five: daughter Sabine is now five years old, Andri was born in Chile and baby Noe was born in Australia.  _ the couple thought they would complete their travels in four years, but now, seven years later, they believe it could take seven more. "Since our belief is the need to respect nature, we travel only when conditions are good," Schworer said. The best title of the passage can be   _  .
A. A Swiss family' journey across the world
B. An eco-friendly adventure across the world
C. We have a long way to make a good travel
D. Nature needs respecting and protecting
Answer: