The conclusion of the argument is that new surgical procedures should not be tested in clinical trials. Our premise is that pharmaceutical innovations (which are okay to test in clinical trials) are different from new surgical procedures in that a correctly prescribed drug depends on composition (so there is a systematic way to test whether the drug is correctly prescribed), whereas the effectiveness of a surgical procedure is based on the skill of a surgeon (which is a more subjective standard).
Let's first look at the answer choice you chose:
(D) While it is true that scientific evidence is not given for the dissimilarity, this is not a flaw. We can have a valid argument without scientific evidence for a premise that has been put forth.
Now to the correct answer:
(A) Our argument bases its conclusion on the fact that there is no systematic way to test new surgical procedures, because its effectiveness is based on the individual surgeon who is conducting the surgery. However, what if there was some intrinsic or inherent detail about the new surgery that created a systematic way of gauging effectiveness of the new surgery? For instance, what if the new surgery, was inherently harmful regardless of which surgeon performed the surgery? Then there would be a reason to test the new surgery in clinical trials. So, this is why the argument is flawed, because there can be an inherent way to gauge the effectiveness of a new surgery, as is the case with pharmaceuticals. When you see the words "does not consider" the answer choice is offering a scenario, and if that scenario weakens the argument, that is the flaw of the argument.
Hope that helps! Let me know if you have any other questions.
