The 48-year-old photographer and adventurer with his trademark black and white beard and shoulder-length hair is also an environmentalist devoted to protecting the source of the Yangtze River.And he likes his new nick-name, "garbage cleaner at the source of the Yangtze River".      Yang Xin , is the founder of Green River, one of the country ' s biggest non-govemmental  organizationsto protect the  country's major rivers.      The Yangtze River begins from glaciers in the Tanggula Mountains on the Qinghai-Tibet Plateau.      Garbage was rarely seen in the area about 20 years ago, Yang said, as local nomadic people ledtraditional self-sufficient lives, living in tents. Thanks to increasingly convenient transportation, they ' ve started to use modern products packed in plastics, which can ' t degrade naturally.      "They don' t have a waste management system and just throw rubbish away like before. So tons of garbage are left on the grasslands and river ways," said Yang.      He founded a group with the purpose of dealing with garbage such as plastic bottles, batteries, lunch boxes and so on.      In 1997, Yang and his group founded the Sonam Dhargye Nature Preservation Station in the Hoh Xil Nature Reserve, in memory of the anti-hunting hero who sacrificed his life to protect Tibetan antelopes. Why does Yang Xin get his nickname "garbage cleaner at the source of the Yangtze River " ?
Because he is devoted to the care for the Yangtze River. Because he is a founder of the Yangtze River. Because he worked as a garbage cleaner. Because he is a photographer and an adventurer.
Question: The 48-year-old photographer and adventurer with his trademark black and white beard and shoulder-length hair is also an environmentalist devoted to protecting the source of the Yangtze River.And he likes his new nick-name, "garbage cleaner at the source of the Yangtze River".      Yang Xin , is the founder of Green River, one of the country ' s biggest non-govemmental  organizationsto protect the  country's major rivers.      The Yangtze River begins from glaciers in the Tanggula Mountains on the Qinghai-Tibet Plateau.      Garbage was rarely seen in the area about 20 years ago, Yang said, as local nomadic people ledtraditional self-sufficient lives, living in tents. Thanks to increasingly convenient transportation, they ' ve started to use modern products packed in plastics, which can ' t degrade naturally.      "They don' t have a waste management system and just throw rubbish away like before. So tons of garbage are left on the grasslands and river ways," said Yang.      He founded a group with the purpose of dealing with garbage such as plastic bottles, batteries, lunch boxes and so on.      In 1997, Yang and his group founded the Sonam Dhargye Nature Preservation Station in the Hoh Xil Nature Reserve, in memory of the anti-hunting hero who sacrificed his life to protect Tibetan antelopes. Why does Yang Xin get his nickname "garbage cleaner at the source of the Yangtze River " ?
A. Because he is devoted to the care for the Yangtze River.
B. Because he is a founder of the Yangtze River.
C. Because he worked as a garbage cleaner.
D. Because he is a photographer and an adventurer.
Answer: