同学你好，它的定义如下：

A bilateral transaction involves a trade negotiated between two participants, with price, quantity and other trade data known only by the parties involved. Since bilateral transactions do not occur on regulated exchanges, such transactions are referred to as "off-exchange" or "over-the-counter" (OTC) transactions.

Typically, the types of trades that are negotiated bilaterally include swaps, forwards, and certain complex options.

可以看到，bilateral transaction是场外交易、缺乏监管的，风险会比较大，不符合题意