As an Object Moves from Point a to Point B

Multiple Choice

As an object moves from point A to point B only two forces act on it: one force is nonconservative and does −30 J of work, the other force is conservative and does +50 J of work. Between A and B,

A) the kinetic energy of object increases, mechanical energy decreases.
B) the kinetic energy of object decreases, mechanical energy decreases.
C) the kinetic energy of object decreases, mechanical energy increases.
D) the kinetic energy of object increases, mechanical energy increases.
E) None of the above.