I’m happy to help. As always, let’s start with the question stem. We are looking for the answer that, if true, would provide the most support for the conclusion in the passage.
What is the conclusion? It is the final sentence: that it is generally unwise for patients to have medical checkups when they do not feel ill. The rest of the passage speaks to problems regarding a physician’s thoroughness: both the problems if the physician is too thorough, and problems if the physician is not thorough enough. The correct answer, answer B, links an issue related to thoroughness (namely unnecessary medical tests) with a reason not to have a checkup when ill: that the unnecessary test can CAUSE people to become ill. That supports the conclusion, as it explains why the statement in the passage about thoroughness is connected to not going to a medical checkup when one does not feel ill.
E is incorrect because it does not provide such linkage. Instead, it simply asserts that physicians can eliminate the need to order certain tests by carefully questioning patients. That does not support the conclusion that “it is generally unwise for patients to have medical checkups when they do not feel ill.†It is just a non sequitur.
I hope that helps! Please let us know if you have further questions.