Which statement correctly explains mechanical advantage?



A.
It is the factor by which a machine shortens the length of time needed to do a certain job.


B.
It is the number of times a machine multiplies the effort force put into the machine.


C.
It is the distance over which a machine can move an object in one minute, at a set speed.


D.
It is the amount of force needed by a machine to double the efficiency of the machine.