Answer:
This is basically Simple Harmonic Motion - where the wave disturbance is in the same direction as the wave direction.
That describes (B).
note that y = A cos ω t where the disturbance is y and ω the the angular frequency and is in the same direction as the disturbance y
This seems the make (D) a satisfactory answer
The projection of the disturbance y is perpendicular (sinusoidal) to the time axis, but the disturbance is still in the same direction as the wave motion