Why is B right and C wrong?

In the argument, G says that C is right there is a problem, but only because they aren't listened, and that if there were a licensing body, the problem would dissipate. That is, he agrees that unlicensed experts are problematic, but licensed ones would not be. This is a good match for b. He defends the profession by limiting its valid application to the hypothetically licensed members. C is wrong because I don't think we have specific evidence that he uses to defend anything, and I'm not sure what the general principle would be. Perhaps it would be that handwriting analysis can be a valid form of evidence, but he doesn't cite specific evidence.