Answer:
Part A: foreshadowing 
Part B: to build suspense
Explanation:
In the sentences from "The Cask of Amontillado," the author Edgar Allan Poe makes use of foreshadowing as a warning of the future events in which Montresor murders Fortunato by immurement. In that respect, the dampness of the cellar makes Fortunato cough first, so his expression that he will not die because of a cough creates uncertainty. In fact, coughing involves expelling air, which he will lack after Montresor entombs him. Besides, Montresor pretends to be worried about Fortunato's health, when in fact he intends to kill him.
 
        
             
        
        
        
Hello. You did not inform the speech to which this question refers, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
If King was trying to be persuasive, lines 307 - 334 can only affect persuasiveness by reinforcing the argument King is making. This can be done through a clear and objective diction that reinforces the importance of King's words. In addition, these lines can create a logical, ethical or emotional structure for the speeches, proposing a greater connection between king and the public.