Answer:
A. by completing the speaker’s thought
Step-by-step explanation:
This couplet doesn't seem to be specially sarcastic nor have any sort of emphasis on sarcasm or of any other kind in derived from the couplet structure. There's also no description of the king's action, therefore, we are left with "by completing the speaker’s thought", which it does seem accurate, since the second sentence does complete the larger meaning of what is being said.