Answer:
Add more substrate.
Explanation:
First let's explain why all the other options are wrong:
A competitive inhibitor is a substance that resembles the substrate that normally reacts with the enzime, so it binds to the enzime's active sites and prevents the substrate from doing so. Adding more substrate makes it more likely than a substrate molecule binds to an enzime's active site instead of the inhibitor ("it will outcompete the inhibitor and increase the reaction rate").