Answer: (D)
Starlight Creations can build a pipeline of leadership talent by "providing leadership coaching".
Step-by-step explanation:
By "providing leadership coaching" to younger employees (especially in middle management) within the organization, Starlight Creations can fill the gap that will soon be left when most of upper management retires in five years time.
The leadership coaching will prepare younger employees for the upper management role and also save the company costs of having to hire external employees to fill the vacant positions.