No exact number is listed from what I've seen, but they are on the endangered list. More on the lower side.
The Great Wall stretches across North China from east to west for over 6,000 kilometers. It extends from the shanhai pass at the seaside in the Hebei province in the east to the Jiayu pass in Gansu province in the west.
I believe that the answer is A.
wym???.........................
