The rate at which the reactants of a chemical reaction form the products is called the reaction rate. This concept is crucial in understanding how fast a reaction occurs.
In the context of your question, the correct answer is:
B) Rate/products
This is because the rate of a chemical reaction is specifically about how quickly reactants are transformed into products.
Understanding the reaction rate is important in various fields like chemistry, biology, and environmental science. By studying reaction rates, scientists can optimize industrial processes, design new drugs, and understand environmental changes.