Hi saranshpuri,
My response goes like this-
The first statement makes a generalization that a person who lacks knowledge= incompetent to pass judgement.
For example, if there were a critical scientific discussion, a person not having sufficient knowledge would not be competent enough to make a judgement. A similar contrast is portrayed in issues or matters to judge if a policy by a political party is fair or not. The conclusion says that only seasoned politicians are competent. A weakness in this implication can be understood by assuming that there might be a possibility that a seasoned politician might make a judgement in favor of his/her own political party. Hence, the generalization fails when applied to political issues.

The option 'A' parallels my discussion.
Please let me know the OA.
Thanks in advance.

I might just step in here to say a few words about this particular question and similar questions of this type.

This is an LSAT question that calls for you to point out the flaw. It is different from a weaken question in that with a weaken question you choose an answer that actually weakens the argument - for this question the answer choices are descriptions of the reasoning (the flawed reasoning). So the argument is already flawed you just describe exactly how.

In order to show the flaw in the reasoning you want to break the argument down into evidence and conclusion.

The conclusion is that "only seasoned politicians are competent to judge whether a particular political policy is fair to all."

So what is it that makes seasoned politicians different from other people? How is it that only they are "competent to judge whether a particular political policy is fair to all"?

The evidence is " political know-how is a matter, not of adhering to technical rules, but of insight and style learned through apprenticeship and experience"

Presumably then seasoned politicians have "political know-how." But how does that take you to "competent to judge whether a particular political policy is fair to all"? These things are not the same are they? Political know-how is not the same as Judging the fairness of a policy.

Therefore, answer is D

Note: As an LSAT question this is a little more technical than a GMAT question of this type might be.

A is not correct because relying on a generalization about a characteristic is not always wrong. In fact that is how we categorize things. Reasoning from the general to the specific is the excepted method for Critical Reasoning. "All dogs have tails. This is a dog so it has a tail." The incorrect way is to go from the specific to the general. "My dog has a tail, so all dogs must have tails."

The problem is not the use of a general trait but the shift in language between political know-how and judge the fairness of a policy.