please help quickly

Rubia was given a type of inclined plane called a ramp in her science class. Her teacher told her that the ramp should have a mechanical advantage of 3.



Rubia pulled a block up the ramp, but afterward she calculated that the mechanical advantage of the ramp was 2.8 instead of 3. Her teacher said she did not make a mistake. What did Rubia calculate?
A.
the actual operating power of the ramp
B.
the actual mechanical advantage of the ramp
C.
the ideal mechanical advantage of the ramp
D.
the ideal operating power of the ramp