The Reason an Increase in Substrate Concentration Will Not Increase

The reason an increase in substrate concentration will not increase the reaction rate indefinitely is because

A) eventually the enzyme will no longer recognize the substrate.
B) the active site will become saturated with substrate and the enzyme will not be able to go any faster.
C) another enzyme will take advantage of the excess substrate and use it for a different reaction.
D) enzymes cannot be used over and over in a reaction.
E) the enzyme will become denatured.