Which is the result of using a machine? a) the mechanical average makes the work output greater than the work input? b) the machine can put out force without having force applied to it c) a large force can be exerted through a long distance to have a small force exerted through a small force d) a large force can be exerted through a short distance to have a small force exerted through a long distance

Correct Answers is A.

The machines gives us some mechanical advantage. This means the mechanical average makes the work output greater than the work input
Simple most example is a lever. The force applied is smaller and the output work is larger as compared to input.

Option B cannot be true, as there must be a force to get some work done.
Option C and D are inverse of what a machine is designed for. A small force can be exerted through a large distance to have a large force exerted through a small distance. Common Example of this principle is a screw opener. 

Iwould have to say sorry i can't elaborate more. hope this though!