Here is my opinion -
E does not say when the substantial changes are going to take place. For all we know it might take 2 years.

bagrettin, you are right. That's exactly the reason why E is incorrect. Thanks.

E strengthens the premise, not a weakener, because if it does start to advertise now, then the chip peripherals would have better opportunity to make the adjustments, which in turn will help the chip sell more, so IMO C is the correct choice and not E

(D) Plexis’ major rivals in the computer chip
manufacturing business are developing a chip
with capabilities that are comparable to those of
Plexis’ new chip.

This was tricky...

Can anyone explain why D is wrong.

The stimulus presents that initial sales of New Chips will be maximized if they start the advertising 12 months in advance. However Plexis decides to wait for 6 months. We have to find the best reason why plexis has postponed the advertising.

Choice D: could this be the reasoning: If Plexis started advertising 12 months before the date of release than the rivals will update their product with similar features that will make their product more competitive with plexis. Ultimately that will hurt the initial sales of new chips.
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Dear Rocket7 & shoumkrish,

I'm happy to respond.

Here's the prompt:
The Plexis Corporation, a leading computer chip manufacturer, is currently developing a new chip, which is faster and more efficient than any computer chip currently in use. The new chip will be released for sale in twelve months. Plexis’ market research has shown that initial sales of the new chip would be maximized by starting to advertise it now, but the company has decided to wait another six months before doing so.

Which of the following, if true, provides the Plexis Corporation with the best reason for postponing advertising its new chip?
We know that the new chip will be faster & more efficient than anything currently available. It will be ready in 12 months.

(C) Advertising the new chip now will significantly decrease sales of Plexis’ current line of computer chips.
Suppose this is 100% true. Then we know for sure that Plexis will lose money now. This is a clear and unambiguous reason not to advertise now.

(D) Plexis’ major rivals in the computer chip manufacturing business are developing a chip with capabilities that are comparable to those of Plexis’ new chip.
Suppose this is 100% true. What do we know? When will these other manufacturers start to advertise? We don't know. When will these competing product be release for sale? before or after 12 months from now? We don't know. If these other manufacturers found out about Plexis' new chip, what would their response be? Would they be able to mimic what is great about the Plexis chip? We don't know.
There's a ton that we don't know about (D). Yes, we could imagine some scenarios in which this also would be a clear reason to delay the advertising, but other readings don't support that conclusion. This is vague and suggestive, leaving a lot of room in which we can read things--highly characteristic of GMAT CR trap answers! This is not a tight clear unambiguous answer. Choice (C) is a much much stronger answer.

That was part of my analysis. I will also say, Rocket7 & shoumkrish, it would be an exceptionally good idea if you read the business tech news regularly. Designing a computer chip is not like designing, say, a T-shirt: it's not as if we can add new features more or less on a whim. The kind of breakthrough that leads to a faster and more efficient chip is a major R&D achievement requiring sophisticated science and engineering. Simply the non-technical general information that would appear in an ad, say, the information that the new Plexis chip can operate at XX speed, would give any competitor zero information about how Plexis was able to achieve this breakthrough. Once the Plexis chips are for sale and the R&D departments of competitors can buy the chips and analyze them, then that's the point at which copy-cat efforts might begin.

Students often vastly underestimate the importance of real world considerations in GMAT CR. See this blog:
GMAT Critical Reasoning and Outside Knowledge

Does all this make sense?
Mike
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