I would Pick E over D.

E mentioned that the ones who did not benefit and the ones who did were medically indistinguishable before the surgery, therefore they could all benefit from the surgery...so the doctor was simply doing it for the best of the patient.

E for me
D doesnt answer this-the doctor knew that a particular 4th patient was medically weak and will not recover even after the bypass surgery, but nevertheless advised him so, by not informing him about his medical weakness,but made sure he listed the medical risks involved.
E says all the patients were equal in terms of their medical profile and there was no way in which the doc could distinguish the weaker patient.

E for me.
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Consider kudos for the good post ...
My debrief : journey-670-to-720-q50-v36-long-85083.html

In E, it is clearly mentioned that patients are indistinguishable.
==> Doctors before surgery don't know whether it's a practice for their skills or not.

In D, people may be well informed but we are not sure whether doctors at that time did know about the success of the surgery or not.
In case of E, success is unknown.
_________________

Consider kudos for the good post ...
My debrief : journey-670-to-720-q50-v36-long-85083.html

well think about it this way:

for D, it mentioned the risk of the surgery, i think it actually is referring to the survival rate of the surgery (who survived coronary bypass surgery), and it's unlikely that it is referring to whether they will benefit from it?

D is talking about surgery RISKS, which is outside of scope. Risk means, for example, when someone dies from the surgery.

I think sprtng is saying the same thing.

Posted from my mobile device

This is a difficult question, but the correct answer choice is clearly E.

Consider the following analogy, perhaps not the best one but I hope it will be good enough to make the point.

A dealer sells second-hand cars. Last year 75% of the cars didn't present any problems after the sale, whereas the other 25% presented several problems a few months after the sale. Clearly in that 25% percent of the cars sold, the dealer was more interested in making profit that in the security of the people who bought the cars.

Which of the following, if true, most seriously undermines the argument?

-- the dealer didn't know whether the cars had any problems prior to the sale.
-- the dealer equally informed all the customers about the risks of buying a second-hand car.

In this example, I know is not exactly the same, the correct answer choice is clearly the first one. The dealer here could know that the cars were in bad condition, and still convinced the people to buy the cars.

What makes option D incorrect?

If you read closely the stimulus is says

Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense.

IMO the stimulus already acknowledges for the information given, so the doctors could haven given the same information but recommended patients undergo to the coronary bypass surgery even if the doctors knew that the patients would not benefit.

You're kidding about the LSAT vs GMAT comment, aren't you?

I have gone through these discussions but still unable to clear my doubts. Hoping to get some reply.

In the eg: specified the dealer don't know whether the cars had any problems prior to the sale, but he operated on those cars prior to sales. He could have tested his skills(screw up something) or removed few parts for money etc,.
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A dealer sells second-hand cars. Last year 75% of the cars didn't present any problems after the sale, whereas the other 25% presented several problems a few months after the sale. Clearly in that 25% percent of the cars sold, the dealer was more interested in making profit that in the security of the people who bought the cars.

Which of the following, if true, most seriously undermines the argument?

-- the dealer didn't know whether the cars had any problems prior to the sale.
-- the dealer equally informed all the customers about the risks of buying a second-hand car.

In this example, I know is not exactly the same, the correct answer choice is clearly the first one. The dealer here could know that the cars were in bad condition, and still convinced the people to buy the cars.
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As the comparison has to be similar with original CR. All the patients are indistinguishable prior to surgery, but few benefit and few not benefit after operation. This could be due to doctor used non benefit patients for testing(screwing them)

Still confusion why OA is E.
The patients who underwent coronary bypass surgery but who did not benefit from it were medically indistinguishable, prior to their surgery, from the patients who did benefit.

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Really appreciate for your replies.

+1 D