想问下这是哪个知识点呀，辛苦谢谢

问题如下：

You have placed a sell market-on-open order—a market order that would automatically be submitted at the market’s open tomorrow and would fill at the market price. Your instruction, to sell the shares at the market open, is a(n):

选项：

execution instruction.

validity instruction.

clearing instruction.

解释：

B is correct.

An instruction regarding when to fill an order is considered a validity instruction.

考点：交易指令的辨析

这道题说的是你下了一个以开盘价卖出的指令，问该指令属于什么指令。

开市时卖掉股票的指令，这很明显是在确定满足生效条件的时间。Validity instructions indicate when an order may be filled.

execution instruction：indicate how to fill the order,

clearing instruction: indicate how to arrange the final settlement of the trade.