TOEFL Listening: TPO-TOEFL阅读TPO - PX467Q28PFT4D5TSN$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Credit sales and bills of exchange were devices that merchants developed in order to increase their mutual trust. B. Merchants developed ways of finance their sales without having to rely on slow and dangerous shipments of coins. C. Greater trust among merchants led to an increase in credit sales and to the use of bills of exchange that made the shipping of coins unnecessary. D. Merchants began to trust one another when it become too slow and dangerous for a single merchant to ship coins.