[求助]讨论还没确定答案的 GWD17-18

Q18:

Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.

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1. Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.
   
2. Over the course of the eighteenth century a tripling in the average output of ironwork was due to the replacement of charcoal by coal for the fuel used in the smelting of iron ore, in addition to several improvements in blowing machinery.
   
3. With charcoal’s being replaced by coal as the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
   
4. The replacement of charcoal with coal for the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
   
5. Charcoal being replaced by coal as the fuel used in the smelting of iron ore, and several improvements in blowing machinery, which tripled the average output of ironwork over the course of the eighteenth century.

看了讨论 但答案不确定啊  A 还是C 呢

as a result of   and  becaue + 句子 能平衡吗

讨论上有这样说的:"这样的用法其实是可以接受的,就是XDF讲过的平行结构中,功能相同的部分是可以并列的,比如名词和名词性从句是可以并列的,在这里是as a result of引导的原因状语和because引导的原因状语从句的并列"

这观点对吗?

谢谢

as a result of 是副词短语，和后面不能并列，个人觉得