Is the true risk of losses of hedge funds using arbitrage strategies most likely to be understated if that risk is measured by: Standard deviationTraditional value at risk(VaR) measures （）①A. No No ②B. Yes Yes ③C. Yes No

A. ①

B. ②

C. ③

多线程是Java语言的______机制，只能够处理同步共享数据和各种不同的事件。