Most large corporations in the United States were once run by individu

Hi Experts, (GMATNinja, @VeritasKarishma)
In Question 4 option B, [They seldom engaged in short-term trading of the stock they owned.], isn't ''seldom'' extreme? I mean someone at some time could have sold, despite the reduced profits, due to some financial needs. I eliminated this choice for the same reason.
And chose 'D' after POE.
Where did I go wrong? Please explain.
Thank you.

I think the answer here is D. To me, the contenders were D and E.

Going through the choices, my thought process was:

A - antitrust laws apply to large institutions only, and the answer of 'any single shareholder' is too broad.
Today, with few exceptions, the stock of large United States corporations is held by large institutions-pension funds, for example-and because these institutions are prohibited by antitrust laws from owning a majority of a company's stock

B - this is a proposal, not a law or regulation, so the passage does not support this choice. This is in the second paragraph.

C - this choice is a tough one. The passage doesn't make explicit the nexus between policy decisions and the board or managers; the only mention is in the first sentence of the passage. But I think the last sentence of the first paragraph implies management are responsible for policy decisions - there's no mention of the board in making decisions. Or put another way, you need to negate the answer by making an inference, and here it's that boards may provide company policy but it's management that makes the decisions.
As a result, United States productivity is unlikely to improve unless shareholders and the managers of the companies in which they invest are encouraged to enhance long-term productivity (and hence long-term profitability), rather than simply to maximize short term profits.

D - I think the relevant line was too clear, making me more than suspicious that I've selected the wrong answer!
Because putting such large amounts of stock on the market would only depress its value, they could not sell out for a quick profit and instead had to concentrate on improving the long-term productivity of their companies.

E - this one looks like a stretch. Using the final line of the first paragraph (again), my take is that companies are currently run to maximise short term profits, but there is no linking of productivity and stock values in the short term. If I was looking for a way to negate the answer, putting on my investor hat, I'd say investors are influenced by quarterly earnings (or similar) so any news that companies are trying to increase productivity should increase the stock price.

As I note above, E was one of my contenders. My rationale at rejecting the answer was that the passage refers only to long-term productivity, so we have nothing about short-term productivity to draw any inferences. It also helps that the relevant part of the passage for choice D was pretty clear (I think it is!). Still, my answer, and therefore my reasoning, could be wrong.

I would love to know the answer for this one if someone is willing to help out.