Hey folks,

The key thing here is to figure out what two things we are comparing:

• "Tides typically range from three to six feet, but while some places show no tides at all, some others, such as the Bay of Fundy, have tides of at least thirty feet and more."

So we are comparing "some places" to "some other[ place]s". We are comparing places to other places - this makes sense.

However, in D and E, we are comparing "some places" to "those [tides] at the Bay of Fundy" and "the ones at the Bay of Fundy". So now we're comparing places to tides. This comparison doesn't make much sense. We can eliminate D and E.

B we can eliminate based on sentence structure. We can see this better by cutting out our first independent clause ("Tides ... feet") and our descriptive phrase ("such ... Fundy"). Remember, 1) if two parts of a sentence are separated by comma + a conjunction, they should both be able to stand alone as a complete sentence and 2) if something if set off by commas is a sentence, we should be able to take it out of the sentence without destroying the grammar.

• "While some places show no tides at all, the others that have tides of more than thirty feet. "

Let's further cut out "while ... all" to see this better:

• "The others that have tides of more than thirty feet."

This is not a complete sentence on its own, which means we have a sentence fragment. Eliminate B.

Deciding between A and C is a matter of concision. They're both grammatically correct, and they both say the same thing, but C is shorter. On the GMAT, shorter is better as long as meaning and grammar are preserved. We can eliminate A and pick C.