This leads to the wrong conclusion. The advocate doesn’t conclude that there should be more caution in assessing TMD’s overall risks. He concludes that the use of TMD has not been shown to be acceptable.

Wrong trigger. We already know that most of the population (80%) does not eat peaches and is thus unlikely to ingest TMD. So (B) can’t help justify the conclusion that TMD hasn’t been shown to be acceptable.

Or: if a pesticide is not used for its intended purpose or it has not been shown to be safe for the whole population, then its use is not acceptable. TMD hasn’t been shown to be safe for the whole population. So (C) supports the conclusion that TMD hasn’t been shown to be acceptable.

The advocate uses small children as an example, but she doesn’t conclude that society has a special obligation to protect small children from pesticides. Also, we know that average doses are low and are safe, so (D) wouldn’t trigger anyway.

We don’t know that TMD was meant to protect the population from harm. We also don’t know that it’s causing serious harm to some people. The author’s just arguing that it hasn’t been shown to be acceptable, since it hasn’t been shown to be safe for everyone.