单选题：Building Renovation　　In cities across the United States, old

　　Building Renovation
　　In cities across the United States, old factories,warehouses,schools, railroad stations and other buildings are being renovated for new uses. City planners and private investors are finding that good buildings, no matter how old, can be remodeled for new purposes. "If you'd asked someone four or five years ago whether he'd rent an apartment in an abandoned piano factory or clothing warehouse, he' d have thought you were crazy," says a New York architect. "Today, many people are eager to do it. " The, renovating may include a former city hall or courthouse changed into offices;a bank or church changed into a restaurant; or, as in Plains, Georgia, a railroad station used as a center for a presidential campaign.
　　Only a few decades ago, renovation was unpopular and generally far more expensive than taking down abandoned buildings, and starting from the beginning.A change began in the 1960s with a number of well-advertised projects, They included Ghirardelli Square in San Francisco,where an old chocolate factory was restored and made into shops and restaurants; Trolley Square in Salt Lake City, where abandoned car warehouses became a shopping mall;the Soho District of New York City, where unused warehouses were made into artists' studios and apartments.
　　What caused the change? "One reason is nostalgia,"a San Francisco builder suggests."Maybe old is better than new, many people are saying, Feelings about preserving attractive or historic buildings have changed a great deal. " A second cause is economy. The cost of tearing down an old building and constructing a new one from nothing now has risen to the point where it is often less expensive to fix a solid older structure. Also builders realize that fixing up an existing building often requires no new permits, sewer lines, or water connections.
　　Even when the costs of restoration are the same as or a bit more than the costs of putting up a new building, fixing the old building may be better. A Boston architect says,"The advantage comes when you can develop a final project that is more desirable than a new building one with the right location, more space, more floor area, a special character, materials of a particular quality. " Gradually, architects and builders are developing knowledge about renovation and preservation, bringing imagination and creativity to the job．In the United States, renovating old buildings_________ A．has had a long history
B．is becoming increasingly popular
C．is still unpopular
D．has just caught the fancy of architects and builders