Final answer:
The correct answer is option D) Formal address.
Step-by-step explanation:
In the passage where Prince Eric is seeking permission from the king, the phrase "With your permission, sire" is an example of a Formal address. This is because Eric is using a respectful and polite form of speech appropriate for speaking to someone of higher status, such as a king. It is not a simile, metaphor, or alliteration, as those are all figurative language or sound devices.
Similes and metaphors make comparisons, with similes using "like" or "as," and metaphors doing so without these words. Alliteration is the use of the same consonant sounds at the beginning of closely connected words. Since none of these definitions apply, we can conclude that the literary device being used is Formal address.