the correct answer is product
In a chemical reaction the enzyme plays an important role in catalysing the reaction.
the enzyme has an active site on its structure to which a substrate can come and bind. The active site has a specific shape to which the substrate of complementary shape can come and bind. once the substrate is bound to the active site of the enzyme the reaction takes place and a product is formed. Once the product is formed, product is released from the active site and enzyme remains unchanged at the end of the reaction.
therefore answer is product that is released from the active site