sat的问题

残缺成分，比如缺主语谓语之类的
我举个例子：
A relatively new breed of cat, the Munchkin, bred to have extremely short legs,(横线：with the added advantage is that they are usually unable to jump up on) furniture.
A:with the added advantage is that they are usually unable to jump up on
B:has the added advantage that it is usually unable to jump on
选B不选A因为主语是cat，接谓语has the added advantage……
所以这就是Fragment错误