请高手指点一题 (刘振民语法里面的)

4-12

For many people, household labor remains demanding even if able to afford household appliances their grandparents would find a miracle.

C. even if they can afford household appliances their grandparents would have found miraculous.

E. even if they are able to afford household appliances which would have been a miracle to their grandparents.

很明显错误的选项我就不贴出来了，答案是C, 解释是因为 can 优先于 be able to，我觉得这个解释太牵强了。因为如果是选C的话，那整个句子不就有三个谓语动词，但是只有一个连词？？？那这种错误不是应该更不能原谅马？如果解释成 appliances that their.. 省略了that,  那么如果后面直接是 found.. 我可以理解，但是用了would have found.

请高手指点一下！谢谢了

谢谢啦！！