Answer: 
Enzymes are biocatalysts which increases the rate of the biochemical reaction by lowering the activation energy of the reaction. 
It performs the catalysis in four steps: 
- The substrate enters the active site of a specific enzyme. 
- It forms the enzyme-substrate complex with the help of non-covalent interactions such as complementary shape, hydrophobic interactions, hydrogen bonding et cetera. 
- The process of catalysis takes place during which old bonds are broken or rearrange to convert the substrate into the product. It results in the formation of enzyme-product complex. 
-  The product has different properties as compared to the substrate due to which it gets released from the active site of the enzyme. The enzyme is ready to bind to a new substrate. 
Thus, the correct answer would be the formation of the enzyme-substrate complex.