actually, all of your eliminations have some element of truth but are all flawed in some way:
1) the word "having" is not always wrong, but it is in this case. make sure you know why..
2) you should not get rid of answer choices because other choices have idioms you like. get rid of them because they are wrong on their own. the problem is that if you indicate few people that means you're pointing them out..
3) D is 100% parallel; its parallelism just creates an absurd meaning..
4) don't ever pick an answer choice because it gets something right. pick it because all the others are wrong..[/quote]
Can you please explain how D is parallel.
"have reduced" and "are not making"
The first one is present perfect whereas the latter is present continuous.
Shouldn't the tense on both the sides of parallel marker be the same. Though I know that there are situations where the aforesaid need not necessarily be true but what about in this case.
Also can you please throw some light on when the tense on either side of the parallel marker is same and when it is not.