numbers of fines/amount of fine

[mamajonov]

The administration has increased the number of fines for mining safety violations as part of their campaign to protect miners.

a. has increased the number of fines for mining safety violations as part of their
b. have increased the number of fines for mining safety violations as part of their
c.has increased the number of fines for mining safety violations as part of its
d. has increased the amount of fines for mining safety violations as part of its
e. have increased the amount of fines for mining safety violations as part of their

I chose D, but the correct answer is C. Then I read the expanation of the answer and agree with it.
However, D also still makes sense in my opinion. For example, if there were two fines, say that 50$ and 100$ for violation A and B respectively, then govenrment increased the amount of fines, making 80$ for violation A and 100$ for violation B.
Your explanation is highly appreciated.Thanks in advance

[RonPurewal]

Where (and when) did you see this question?

[mamajonov]

I came across on May 25, 2013 in my CAT3.

[RonPurewal]

I came across on May 25, 2013 in my CAT3.

Ok. This problem was removed from the CAT software several months ago, for precisely the reason you're talking about here. (Interesting that you'd wait 6 months to ask about it!)

[mamajonov]

Thanks for the reply. Yes, it is too late to ask that question. I had a GMAT test in September but did not achieve my target. Now, I am reviewing all the problems I did before as a preparation to retake.

[RonPurewal]

Ok. Yep, we killed this one.
Good luck.