生态效率可表达为以下哪种（ ）方式 Eco-efficiency can be expressed as（ ）

A、某系统的经济产出除以该系统生产的产品数量 The economic output of a system divided by the quantity of products produced by the system
B、某系统生产的产品数量除以该系统的经济产出 The quantity of products produced by a system divided by the economic output of the system
C、某系统生产的产品数量除以该系统产生的环境负荷 The quantity of products produced by a system divided by the environmental impacts generated by the system
D、某系统产生的环境负荷除以该系统生产的产品数量 The environmental impacts generated by a system divided by the quantity of products produced by the system