It has to be A since it's the only one that describes both the financial effects and emotional effects because of the inappropriate words.
Start a fire. It sets the entire island on fire and puts them in danger. As far as irony goes, fire is a symbol of hope in the novel, so it is ironic that hope is the thing that would destroy them (if they were not found just in time).
In a chemical reaction<span>, substances (elements and/or compounds) called </span>reactants<span>are changed into other substances (compounds and/or elements) called </span>products<span>. You can't </span>change<span> one element into another in a </span>chemical reaction<span> — that happens in nuclear </span>reactions<span>.</span>