To increase productivity, the clown factory decides to have a contest. the person who completes the most clowns on monday does not have to come to work on tuesday. the factory is using reinforcement as a motivator.

The factory is using negative reinforcement.

You can either have reinforcement or punishment and either of those can be positive or negative. Reinforcement is used when you want a behavior to continue. Punishment is used when you want to stop that behavior from continuing. Positive means you gain something and negative means you get something taken away/stopped. 

Since the factory wants it's workers to continue making more and more clowns, reinforcement is being used. Since the factory will take away the requirement of having to come to work on Tuesday, the reinforcement is negative.

If u don't know the answer, always guess "c"