The option which would most likely result in the greatest decrease in the rate of a chemical reaction is adding an enzyme inhibitor to a reaction catalyzed by an enzyme.
Enzyme inhibitor is known for slowing down any processes, especially when it comes to chemical reactions, so I'd say A is the correct answer.
Parenchyma
phloem
<span>xylem</span>
The answer is 4Fe+3O2→2Fe2O3
