结算账户开户档案自销户之日起至少保管（）年，交易记录自交易记账之日起至少保存（）年。（）
A.5，5
B.5，7
C.10，5
D.7，5
参考答案：A
An analyst does research about future transaction. In general, which of the following is least likely to prefer for an investor to terminate a future contract at expiration（）
A. Delivery.
B. Closeout.
C. Cash settlement.
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