Which kind of disturbance is created by moving a spring toy up and down? perpedicular to the wave motion

in the same direction as the wave motion

in a circular motion

parallel to the wave motion

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

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it