请老师帮忙解答一下

问题如下：

选项：

A.Exchange-traded funds

B.Commodity trading advisers

C.Bank proprietary trading desks

解释：

A is correct. Exchange-traded funds are part of a class of institutional investors referred to as real money accounts. They are usually restricted in their use of leverage or financial derivatives in their accounts.

B is incorrect. Commodity trading advisers are part of the professional trading community that uses leverage or financial derivatives in the management of their accounts.

C is incorrect. Proprietary trading desks at banks are part of the professional trading community that uses leverage or financial derivatives in the management of their accounts.

中文解析：

A正确。交易所交易基金是一类机构投资者的一部分，被称为真钱账户。他们在账户中使用杠杆或金融衍生品通常受到限制。

B不正确。大宗商品交易顾问是专业交易群体的一部分，他们使用杠杆或金融衍生品来管理自己的账户。

C选项不正确。银行的自营交易部门是专业交易群体的一部分，他们使用杠杆或金融衍生品来管理自己的账户。