How does a lever apply forces with advantage?

Question

How does a lever apply forces with advantage?

 A. 

It applies a small amount of force to produce a large amount of force.

 B. 

It gives the advantage of change in direction of the effort force.

 C. 

It decreases the distance needed to move an object.

 D. 

It increases the force needed to move an object.

Answer 1

To be honest, this question cannot be answered as asked. Depending on the class of lever, any of the answers could be correct. 1st class levers are usually used to reduce the input force (A) but could also be to change the direction of the force only (B) - think of a pulley that doesn't move, you don't change the magnitude of the force, but changing the direction makes it "easier", and pulleys are just a variation of levers. 3rd class levers often increase the input force (D) so that the output distance can be greater. (C) is the biggest stretch, but if you think of a typical door handle, you're using a 2nd class lever moving your hand farther, allowing the "object" to move a shorter distance (with a greater output force).

So, short answer - the author of the question PROBABLY meant A, but the other 3 could be justified.