Prep1-134-关于从句和分词修饰

Prep1-134:

Among lower-paid workers, union members are less likely than nonunion members to be enrolled in lower-end insurance plans imposing stricter limits on medical services and requiring doctors to see more patients, and spend less time with each.

(A) imposing stricter limits on medical services and requiring doctors to see more patients, and spend

(B) imposing stricter limits on medical services, requiring doctors to see more patients, and spending

(C) that impose stricter limits on medical services, require doctors to see more patients, and spend

(D) that impose stricter limits on medical services and require doctors to see more patients, spending

(E) that impose stricter limits on medical services, requiring doctors to see more patients and spending

请问，如果A当中逗号去掉，答案会不会有变化。另外，从句和分词是本题的考点吗，请帮忙解释

这个spending做从句中的一个非谓语动词的伴随状语？

分词做伴随状语不都是修饰整个句子吗？

请大家帮忙解释一下，谢谢！

显然被选项的内容应该是修饰plans的。从这个角度看，plans只会 impose stricter limits ... and require doctors ... 不会spend ...，所以需要impose / require 平行，而spend不能平行，这样排除BCE，剩下AD。相比D好一点，所以这题是不是就是体现选最优的策略呢？

如果D改为 that impose .... and require doctors to see more patients and (to) spend (less time with each.) 即将to see 和 to spend对应，是不是更好一点？

继续请教大家

(A) imposing stricter limits on medical services and requiring doctors to see more patients, and spend

(B) imposing stricter limits on medical services, requiring doctors to see more patients, and spending

(C) that impose stricter limits on medical services, require doctors to see more patients, and spend

(D) that impose stricter limits on medical services and require doctors to see more patients, spending

(E) that impose stricter limits on medical services, requiring doctors to see more patients and spending