Hi psm12se,

In this SC, there are several grammar rules that you can use to eliminate answers and hone in on the correct answer. If grammar isn't one of your strong suits yet, then try thinking of grammar as a "matching game." If you know one part of a pair, then you should be able to figure out the other part. For example:

1) At the end of the answer choices, you'll notice the words "is" and "are"; this is a verb issue that is based on a singular noun vs. a plural noun. Find the NOUN and you can choose the matching verb. In this case, the noun is "a mix...", which is singular....so the verb must be "IS"

2) At the beginning of the answer choices, you have 2 options: "known" vs. "is known"; since the SC discusses "a drilling technique...", we should use "known as" because it's one type of drilling technique ("a drilling technique known as hydraulic fracturing"). If there was one and only one drilling technique in real life, then you would use "is known as".

3) The final grammar rule is a style rule based on the words where/when/in which. Since this SC isn't describing a place, the word "where" would be incorrect. "In which" is the proper style.

These rules all point to answer B.

The good thing about SCs is that they're based on established rules that can be learned. The bad thing is that there are a lot of rules (especially minor rules called usage, style and idioms) and if you're trying to pick answers based on "how they sound", then you're likely to make a bunch of silly mistakes. Learn the grammar and use the answers to your advantage and you can pick up a lot of points in this category.

GMAT assassins aren't born, they're made,
Rich