CE我实在比不出来，求助啊

bunnyfdu2015

So dogged were Frances Perkins' investigations of the garment industry, and her lobbying for wage and hour reform was persistent, Alfred E. Smith and Franklin D. Roosevelt recruited Perkins to work within the government, rather than as a social worker.

	and her lobbying for wage and hour reform was persistent,
	and lobbying for wage and hour reform was persistent, so that
	her lobbying for wage and hour reform persistent, that
	lobbying for wage and hour reform was so persistent,
	so persistent her lobbying for wage and hour reform, that

答案E,请问C怎么错了啊？我做这个还有点小晕

吃饭睡觉打豆豆

从结构上说，这两个逗号之间的部分就没名分。。。干啥的呢？
逻辑上也说不通，划线部分应该是和前面so引导的部分是平行的，没有so也不合理。
不过我也很不喜欢E这个答案哎，感觉so前面加个and 舒服点。
小菜刚刚开始看g希望各位大神指点。