More than 4,000 years ago, a primitive (上古的)artist carved a picture on the side of a rock in northern Norway. The carving described a man on a pair of skis, Today, more than 'a million Americans have something in common with that Stone Age character -- they have joined in a fast-growing sport called" ski touring".
Ski touring is healthy, cheap, unpretentious (自然的)fun -- and an excellent winter family activity. It is a more demanding sport and requires first-class physical condition and a good deal of energy. To a ski tourer, the joy of this sport lies in its simplicity. It can be enjoyed wherever there is snow on an open field or road.
As ski touring grows more popular, equipment for the sport is expanding, too. There are now chains of commercial ski touring centers renting and selling equipment and providing instruction. While some members of the family may be chicken about schussing (作直线下滑) down mountainsides, today everybody can go on a touring trip.
Ski touring probably began in ______.

A. North America
B. Southern America
C. Northern Europe
D. Southern Norway