问题如下：
TRR Enterprises sold products to customers on 30 June 2006 for a total price of €10,000. The terms of the sale are that payment is due in 30 days. The cost of the products was €8,000. The most likely net change in TRR’s total assets on 30 June 2006 related to this transaction is:
选项：
A.€0.
B.€2,000.
C.€10,000.
解释：
B is correct.
The sale of products without receipt of cash results in an increase in accounts receivable (an asset) of €10,000. The balance in inventory (an asset) decreases by €8,000. The net increase in assets is €2,000. This would be balanced by an increase in revenue of €10,000 and an increase in expenses (costs of goods sold) of €8,000.
解析：卖了10000块的产品，成本是8000，因此存货减少8000。有30天的延迟付款时间，因此应收账款增加10000。总的来看，资产增加了2000。
请问哪里看出是有30天的延迟付款时间呢？
