Find the next one in the given series.
Given series:

Let's trace the position and orientation of the shaded triangle along the vertices of the hexagon:
1. In the $1^{\text{st}}$ figure, the shaded triangle is at the top-left vertex, pointing inside/clockwise.
2. In the $2^{\text{nd}}$ figure, it moves $1$ step clockwise to the bottom-left vertex.
3. In the $3^{\text{rd}}$ figure, it moves $1$ step clockwise to the bottom vertex, pointing leftwards.
4. In the $4^{\text{th}}$ figure, it moves $1$ step clockwise to the bottom-right vertex, pointing downwards-left.

Following this step-by-step clockwise vertex movement, in the $5^{\text{th}}$ figure, it must move to the right-most vertex, and its arrow direction will turn to face downwards.

This matches exactly with the structure depicted in option $\text{D}$.