Which of the following statement is NOT true about machines?

a
Machines change the size of a force needed to do the work.
b
Machines change the way work is done.
c
Machines decrease the amount of work that is done.
d
Machines change the direction of a force needed to do the work.

c) Machines decrease the amount of work that is done. (This is not true, as machines only change the way work is done and may use less force or effort, but the amount of work done remains the same.)

The statement that is NOT true about machines is c) Machines decrease the amount of work that is done.