NO.PZ2018062007000018
问题如下：
Arbitrage exists when:
选项：
A.Net positive profit is generated at expiration.
B.Net positive profit and net negative loss are generated through the transaction term.
C.Net positive profit is generated at initiation.
解释：
C is correct.
An arbitrageur buys one asset in the cheaper market and simultaneously sells the same asset at a more expensive market, the risk-free arbitrage profit is generated at the beginning of transaction period.
中文解析：
我们在进行套利交易时的过程是，在期初发现价差，预期在期末做多和做空的资产价格趋同，所以套利获得的收益在期初就确定了，也就是C选项所描述的情况。
没太明白B的含义和为啥错
