gmat prep test Q

[sudaif]

The three women, liberal activists who strongly support legislation in favor of civil rights and environmental protection, have consistently received labor's unqualifying support.

a. same
b. are consistetly receiving the unqualifying support of labor
c. have consistently received the unqualified support of labor
d. receive consistent and unqualified support by labor
e. are receiving consistent and unqualified support by labor

My queries:
1) is "support by labor" wrong?
2) what justifies the use of present perfect tense here? Is it the fact that we have present perfect in the original sentence --- which implies that the three women are continuing the receive the support of labor?
3) what is the difference between "unqualifying" and "unqualified"? Unqualified means "without any further conditions"....what does unqualifying mean here?

[tim]

1. yes, "by labor" is wrong. you can receive support from x or you can receive the support of x, but you cannot receive support by x.

2. what suggests that we shouldn't use that tense? if it works and conveys an appropriate meaning, there is nothing wrong with it..

3. who knows? that's why it's wrong. the best i can come up with is that "unqualifying" means that someone is not qualified for something. also amusing to note that my browser marks "unqualifying" as a word not in the spell-check dictionary.. :)