In Weakening questions, what kind of new information can effectively challenge the argument?

The correct choice is based on the idea that weakening an argument involves introducing information that undermines the premises or conclusion drawn by that argument. Contradictory evidence is particularly effective because it directly opposes the claims established by the argument.

When contradictory evidence is presented, it can negate an assumption or a stated fact within the argument. For example, if an argument asserts that a specific treatment is effective based on certain data, providing evidence that contradicts this data can severely weaken the argument's credibility. This new information challenges the validity of the assumptions the argument relies upon, leading to a reevaluation of the conclusion.

In contrast, the other options do not serve as effective means to weaken an argument. Supporting details often bolster an argument rather than challenge it. Historical context could provide a background but does not necessarily contradict the argument, and personal opinions, while subjective, may not provide the firm evidence needed to effectively counter a logical claim. Therefore, presenting contradictory evidence is the most powerful way to weaken an argument since it strikes at the heart of its reasoning and claims.