Grandparents typically use Facebook less than their grandchildren.（）

A．Social networking sites provide more obtrusive,less-tailored advertisements than traditional marketing campaigns．B．Media-savvy businesses can positively affect their customers’ beliefs and counter negative perceptions on these sites．C．Business use of Facebook and similar sites has now grown to nearly 40 percent of global companies．D．Facebook and other sites offer plenty of social opportunities, but companies have been unable to identify practical business applications．