GWD17-Q18前人讨论过，不过没给解答

18. GWD17-Q18:
Over the course ofthe eighteenth century, the average output of ironwork tripled as a result ofseveral improvements in blowing machinery and because coal replaced charcoal asthe fuel used in the smelting of iron ore.

A. Over the course of the eighteenth century,the average output of ironwork tripled as a result of several improvements inblowing machinery and because coal replaced charcoal as the fuel used in thesmelting of iron ore.
B. Over the course of the eighteenth century atripling in the average output of ironwork was due to the replacement ofcharcoal by coal for the fuel used in the smelting of iron ore, in addition toseveral improvements in blowing machinery.
C. With charcoal’s being replaced by coal asthe fuel used in the smelting of iron ore and several improvements in blowingmachinery, the average output of ironwork tripled over the eighteenth century.
D. The replacement of charcoal with coal forthe fuel used in the smelting of iron ore and several improvements in blowingmachinery, the average output of ironwork tripled over the eighteenth century.
E. Charcoal being replaced by coal as the fuelused in the smelting of iron ore, and several improvements in blowingmachinery, which tripled the average output of ironwork over the course of theeighteenth century.
那D为什么前半部分不能使独立主格做伴随状语？我觉得如果前面是伴随状语没有错误啊
并且A太不靠谱了吧，这么明显的不平行当答案
D相对来说已经是最平行的了
求牛牛解答