I'm confused - C seems to introduce a sufficient condition that isn't in the stimulus (that the pesticide is being used for its intended purpose.

I chose E because the pesticide is trying to reduce a harm (pests on peaches) and thus could cause harm to a certain segment of the population (children).

#help

Re: Question 5 - I'm still not sure why the line about scientists discovering phosphorous is a conclusion. It doesn't seem to rest on any of the premises.