In a simple harmonic motion, the velocity vector with respect to displacement vector

Simple Harmonic Motion (SHM) is like a swinging pendulum or a bouncing spring.
Imagine a point moving back and forth in a straight line.
Its position changes constantly, this is the displacement.
Its speed also changes constantly, this is the velocity.
In SHM, the acceleration is always directed towards the center point (equilibrium position) and is proportional to the displacement.

Now, let's think about the relationship between the velocity and displacement.
When the displacement is zero (at the center point), the velocity is at its maximum.
When the displacement is at its maximum (at the extremes of the motion), the velocity is zero.

This means that the velocity is not in step with the displacement; there's a difference of 90 degrees (or π/2 radians) between them.
The velocity vector leads the displacement vector by 90°. This is because the velocity reaches its peak a quarter of a cycle *before* the displacement reaches its peak.
Therefore, the correct option is B: Leads by 90°