问题详情

Themoneymarketisadealermarketwhere,overthetelephoneorthroughelectronicsystems,______.
A．abrokerreceivescommissiontoactasanagent
B．theinvestorsaretradingonacentraltradingfloor
C．firmsbuyandsellsecuritiesintheirownaccounts,attheirownrisk
D．individualinvestorscantradeontheexchange

请帮忙给出正确答案和分析，谢谢！