Passage Summary: Carl is bad at his job because his 'win rate' for solving cases is the worst in the department.

Conclusion: Carl is definitely an incompetent detective.

Reasoning: Carl has the lowest solve rate on the entire police force, having only closed one out of twenty-five cases in the last three years.

Analysis: To weaken this argument, we need to find a reason why a low solve rate doesn't necessarily equate to low skill. In the world of detective work, not all cases are created equal; perhaps Carl is the 'closer' who is only handed the most impossible, cold cases that everyone else gave up on. If his 25 cases were significantly harder than his colleagues' cases, his 4% success rate might actually be a sign of persistence rather than incompetence. Look for an answer that suggests the difficulty of Carl's cases is higher than average.