What principal of a lever is being used in this photograph? 
 A.
 A bottle opener is a type of lever that reduces the input force required by reducing the distance over which the force is applied.
 B.
 A bottle opener is a type of lever that enables the same work to be done over a shorter distance with less force.
 C.
 A bottle opener is a lever in which a smaller input force acts over a larger distance so that a larger output force can act over a smaller distance.
 D.
 A bottle opener is a type of lever that magnifies the output force required.