The correct response is Class 2 and 3.
In a Class 2 lever, the load is between the effort (force) and the fulcrum, allowing for an increase in force applied. In a Class 3 lever, the effort is between the load and the fulcrum, which typically requires more force to lift a load, but instead allows for a greater range of motion or speed.
Class 1 levers can either increase or decrease force depending on the position of the load, fulcrum, and effort.
So, while Class 1 can sometimes increase force, it doesn't consistently do so like Class 2 does. The important distinction here is that Class 2 specifically is designed to amplify the force. Therefore, Class 2 and 3 are the classes of levers where it's possible to see a significant increase in the force applied relative to the load.