Not exactly... Answer choice (C) is saying that leniency is not a trait of the judge but rather a trait of the decision of the judge. The argument is not about where the trait of "leniency" exists. The public advocate is actually arguing that judges should be allowed to be lenient in their sentencing - the public advocate thinks this would lead to more accurate verdicts by juries.
So the issue with answer choice (C) is that it's simply discussing a point about the trait of "leniency" that isn't the subject of the public advocate's argument.