Prospecting for gold during the California gold rush

[LarryM989]

I selected E as the answer because i didnt find a better choice. However one point regarding answer option E is not clear to me. Meaning wise i felt the usage "since erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach of" has an ambiguity . As "Erosion, Prehistoric movement, and ancient, gold bearing riverbeds" are all parallel , it could mean that all these three elements were thrust to the surface by volcanic activity.

When i read the answer option for the first time i read it as below :

Since (Erosion, prehistoric movement , and ancient , gold bearing riverbeds) thrust to the surface by volcanic activity. But logically Erosion and prehistoric movements were not thrust to the surface by volcanic activity.

The answer option D seemed better at first in the parallel construction. However, as putting cannot come after "that thrust gold bearing river beds to the surface", I Eliminated D.

Could someone clarify the meaning of the above clause in the answer option .

[Sage Pearce-Higgins]

Interesting comments. It's good to look at correct answers such as this one to get an idea of what GMAT considers acceptable. First of all, I consider E to be an imperfect sentence. I wouldn't usually consider 'erosion', 'glacier movement' and 'riverbeds' to be parallel since they're different kinds of things. However, when we answer SC problems we need to have an order of priority. The lack of a main verb in some answer choices, and the misuse of 'because of' are more significant issues than the parallel construction, and this problems shows that. As for your alternative reading of the meaning - that all three things were thrust to the surface - I think that's stretching things a bit. Many sentences have a little ambiguity, but we usually apply the principle of charity discount totally absurd meanings. Again, this problem shows what GMAT accepts as a reasonable sentence.

[LarryM989]

Thanks for your response! I shall keep that in mind. What you basically are trying to say is that we need to let go smaller errors on certain sentences when there are bigger grammatical errors in the other options. I too had felt initially that the elements were not parallel and it got me stumped for a minute there. However i understand what you mean and the takeaway here is to let go certain smaller errors such as ambiguity when there are bigger grammatical errors in other options

[Sage Pearce-Higgins]

You're welcome. Good to hear that.