78. A company extends its trade credit terms by four days to all its credit customers. The most likely effect of this change to the company’s credit customers is a four day:
A. increase in their operating cycle.
B. decrease in their operating cycle.
C. decrease in their net operating cycle.

关键是题干的第一句话。我理解的是：公司将其向客户提供的贸易信贷延长四天。从而，也就是应收账款周期增加4天，选A。可答案是C。解释是：A four day increase in payables will reduce the cash conversion cycle (net operating cycle) by four days. 也就是说这是应付账款。
第一句话究竟怎么理解？请教。谢谢。