Final answer:
The grand-vizor's motivation for speaking with the king in private can be inferred as loyalty, based on evidence from the story.
Step-by-step explanation:
The grand-vizor's motivation for speaking with the king in private can be inferred as B. Loyalty.
This inference is based on evidence from the story that suggests the grand-vizor is loyal to the king. For example, in a previous scene, the grand-vizor expresses his dedication to serving the king and protecting the kingdom. Additionally, the grand-vizor's actions and words throughout the story consistently reflect a sense of loyalty towards the king.