Referring to the map above of China with its modern day borders, which of these statements is true regarding the importance of the Silk Roads to the Chinese?

a)A strong and expansive empire was necessary to keep trade routes open.
b)To continue trading with Europe, the Chinese preferred to rely on foreign kingdoms.
c)The trade routes provided quick and easy access to China from Europe.
d)The Silk Roads were one of many alternate routes the Chinese could have used.