TTGWD17感觉每个都有些问题

TTgwdQ18:

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.

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.

为什么是C呢,感觉每个选项都有问题