In the mid-fifth century, Rome was threatened by Hunnish troops who, led by Attila the Hum, demonstrated his military superiority over the weakened, recently conquered city. A: who, led by Attila the Hum, demonstrated his military superiority B: which, led by Attila the Hum, demonstrated their milit...

thanks for replying I'm just supporting the idea of sakali that the plural is needed here. Even if you don't the meaning of the keyword "Quasars", you can find out the word "objects" in the first sentence which explains in detail. In the second sentence, therfore, it should use ...

Thanks for the response. This question was taken directly from a Kaplan 800 book and the official answer is D. I think it has to be one or the other - it can't be both singular and plural. I just don't understand why there are two rules for the same word...and of course the most puzzling part about...

some more thoughts on the usage in B and e pl..... in searching of the idiom about that, i found that 'required of whom to ~', which makes sense the explanation above. Additionally, I quote the original sentence for you. "... the level of effort that will be required of firms to adapt ..."