TOEFL Listening: TPO-TOEFL阅读TPO - 435N7IE59194GG4DN$

According to paragraph 1, why was it necessary to find a new way for European merchants to reach the East? A. People in China were finally ready to trade with Europeans B. The European economy was failing because there was no trade with the East C. Traditional ways of trading with the East had become very costly D. Commercial routes over land had become blocked because of political events