A block is attached to a horizontal spring. On top of this block rests another block. The two-block system slides back and forth in simple harmonic motion on a frictionless horizontal surface. At one extreme end of the oscillation cycle, when the blocks come to a momentary halt, the top block is lifted vertically upward, without disturbing the bottom block. What happens to the amplitude and the angular frequency of the ensuing motion?

a. The amplitude remains the same, and the angular frequency increases.
b. The amplitude increases, and the angular frequency remains the same.
c. Both the amplitude and the angular frequency increase.
d. Both the amplitude and the angular frequency decrease
e. Both the amplitude and the angular frequency remain the same