Answer: Teeth is an example of a wedge. 
Explanation : 
the machines that make our work easier are called simple machines. Some machines can be compound because they are a combination of more than two simple machines. For example, stapler. 
Teeth are an example of a wedge. It is a simple machine which consists of two inclined planes. It is used to split apart objects. 
The mechanical advantage of a wedge is more than 1. 
So, the correct option is (b) " Wedge".